I use the Tournament Director software to run my tournaments, and I've always just used its default payout percentages. Those are:
1-6 players: 70/30
7-9 players: 50/30/20
10-18 players: 46/27/17/10
19-27 players: 42/25/15/10/8
They seem a bit awkward when written out like that, but when you're using software (Excel or tourney director or whatever) and rounding the payouts it works out pretty well. Ultimately it's just personal preference. Also worth noting that my house rule (which is also the TD rule by default) is that rebuys do not count as additional entries to increase the number of places paid. If I have 12 players and 8 rebuys, we're still just paying 4 places.
Some people like flatter payouts. I don't worry about that too much because the main jump is from 1st to 2nd, and in my league players are allowed to make deals heads-up for the money and can modify the payout if they choose (they have to play it out for the points). Some people also would prefer to pay fewer players, like pay only 3 when we have 10 entries. Again, personal preference. But 10 is the point at which we go from 1 table to 2 because I hate 10-handed poker, so for me it's a logical separation point.