[Zag]

I agree with Pete, here, on his comments about game theory. There is a percentage which is the theoretical best percentage against an unknown opponent who is as likely to play too loose as too tight. If all players are playing at this percentage (and they all play equally well postflop) then for one to deviate from this percentage in either direction would be detrimental. (I don't know what that percentage is, exactly, but it is certainly somewhere between 10% and 25%.)

That said, the vast majority of players play too loosely. Given that assumption, the most common case is that you want to be tighter than the others at your table.

I also suspect that the correct percentage of hands that you should play is slightly higher for Omaha than for Hold'em. This is because there is less of an overlay, preflop, of the best hands vs. the worst hands. In Hold'em, you can have a preflop domination of 14-to-1 of As Ah over Ac 6s, for instance. In O8, the most significant level of domination I have found (in 3 tries) is 4-to-1 (Ah As 2h 3s vs. Ac 3d 8h Ks).

I have spent more hours than I care to admit dealing out Omaha hands, hoping to get a feel for the game. Try this: Deal out 6 Omaha hands, and pick the two that you think are best, but leave them all visible. Now deal out 25 of the remaining 28 cards into a 5 by 5 square, so that they represent 10 different boards, 5 rows and 5 columns. Now evaluate all 10 boards for the original 6 hands, giving 1 point to a hand when it wins half a pot, and 3 points for a scoop. Did the two hands that you selected originally finish first and second? I find that they usually don't, not because I selected poorly, but because there is a lot of luck involved.

I have found that the predicted winners in hold'em are the big point winners most of the time.

Note that, if you do the same experiment, but instead you deal the flop before choosing your two winners, and then you deal out 12 different turn & river groups, pretty much the "best" hands will be the winners at the end. In other words, the flop defines the hands pretty well, even when they are not that well defined preflop.

If anyone hasn't played games with himself like this, I highly recommend it. I have found that it really helps with getting the feel of a game.