I do this. I vary from it from time to time, but this is the "base." I'm omitting positions with only one move, like dives to the floor, or running to the corner.
Standing:
[] - quick punch
X - kick
Dir+O - hard punch
O - hard knockdown (ie a clothesline or dropkick)
[]+X - less common hard knockdown, or a "special" like a double-leg, or green mist
Running - [], X, O in increasing order of how big a move they are. Like, it might look like:
[] - shoulderblock
X - kitchen sink, crossbody, maybe a clothesline if they have a bigger move than that
O - lariat probably, unless they have a bigger move than that and they need it here.
This can vary greatly but should be in increasing order. Like, my Roman Reigns starts with a flying lariat on [], Superman Punch on X, Spear on O.
Run Counter - same as above. I usually try to put strikes first, then throws, then holds, so it might look like:
[] - back elbow
X - back body drop
O - sleeperhold
Again, it can vary greatly, but should be in increasing order of "bigness."
Top Rope:
[] - down move
X - down move
O - standing move
[]+X - standing move
If you need three down moves, O remains a standing move, the other three are down.
If you need three standing moves, [] remains a down move, the other three are standing.
If you need four of one type...they're obviously all that type.
Grapple:
[] - basic, non-knockdown punch
[]+up - bodyslam
[]+over - snapmare or other takeover move, like an armdrag, can be an extra strike for brawler types
[]+down - knocking down strike like (usually) a hammer blow, also often takedowns like drop-toeholds or single-legs, can also be regular strikes, good spot for a knee
X - kind of a utility spot, should be something basic to that wrestler; a back switch, a medium strike, good spot for an additional [] strike if needed
X+up - suplex usually; what kind varies more often than whether this is a suplex. Good spot for the medium grapple rana for guys who don't lift. Your basic "throw."
X+over - I like to put headlocks here, although X is good too. Good spot for a more "involved" medium strike, like a short-arm clothesline, or a lower-angle throw, like a gutwrench suplex
X+down - great spot for backbreakers, neckbreakers, or other part-targeting moves, good spot for additional strikes/takedowns, too
O - almost always a strike or submission unless I run out of large grapple slots badly
O+up, over, or down - these will vary so much from guy to guy by this point, they can be anything from additional strikes or holds to big match-enders. Just try to make the direction make sense...up for a brainbuster or chokeslam, down for a piledriver or powerbomb, etc. Also note that ONLY the "O" moves can cause an opponent to get up stunned to set up moves like flying or corner-to-center moves, so make at least one of them a basic strike you won't mind seeing more than once.
[]+X - their biggest, rarest move should go here; for most American-style guys, that's gonna be their finisher, but a fair amount of Japanese guys (and occasionally Americans, too) will have a big, extra-rare super move. You're gonna want that here, in which case their regular finisher would go in whichever "O" slot would make sense - like a powerbomb on O+down. This slot also causes them to stay down slightly longer, so it may also be useful as a setup for diving or running moves instead.
Back Grapple:
[] - whatever you can pick here is fair game
X - very much a utility slot; could be a back suplex if they need more space for bigger moves in O; could be a basic strike depending on the wrestler
O - I usually put holds here, occasionally a pin if a guy doesn't need a hold, but could even be a big move depending on how many they need
O+up/down - often a pin, could be a second hold, could be a second/third suplex...good spot for a less common big move
O+over - usually their main/most common suplex; could be a German, could be a simple back suplex depending on the guy. Could be something else, but guys who throw ZERO suplexes are rare
[]+X - as above, generally their rarest/biggest move, although for some guys, that could be something as straightforward as a rollup. I do like to make this a move they would try to win with. As above, this slot can make them stay down slightly longer; since guys are usually already stunned when you back grapple them, that can be necessary for any move you want to chain into something, so put it here if you need a move like that.
Back Counter:
very straightforward, [] is the weaker move, X is the rarer/stronger
Down Moves:
The long-standing Firepro convention is actually the reverse of how it might seem; O (or "strong") is usually for strikes and other basic moves, X (or "medium") is usually for holds and other more involved moves, including finishers. If that seems backwards, it's because originally X was the pin button, and ALL moves were on O. X then gradually became the pin/submission button, while O became the "everything else" button. Now, we have a pin button again (on a different button) and X has become mostly for submissions, and O mostly for strikes.
Some people would, and probably will, argue that it should be the other way around, and you can do it however you see fit, but that's the "traditional" way.
Corner:
Up+O - superplex. If you have one, it should go here. If you don't have one, a good spot for another lifting move
Over+O - I always, always try to make this strikes if at all possible, or at least something relatively basic. I hate when superplexes are here - you think you're gonna chop the guy and you end up giving him a freakin' brainbuster or something. If everything he does is big shit, try to at least make this the move he would do first.
Down+O - if you have a back superplex, it should go here, unless it's literally the only one you do, then I'd put it on up+O. Most guys don't, so this is a good spot for any big moves like tornado DDTs, split-legged moonsaults, or even a second front-facing superplex.
Ground Grappling:
Mostly just arrange your moves from weakest to strongest. Generally, you'd want your [] moves to be stuff you'd see early in the match, and your O moves to be stuff you'd see later. To that end, I ALWAYS make sure my pro wrestlers have an "O" move I'm okay with them doing late in a match and possibly winning with - or make it a move you can't (accidentally) win with, like a slam. You want all your guys to have these moves, because even if they don't USE takedowns, they can still end up IN these positions depending on their opponent. You (probably) don't want your 20-minute epic ending with some punches because the opponent went for his finisher that happens to be from guard.
Edit: Spunk made a much more succinct version of this post while I was writing mine.
