Maybe by number of level, that is 1 lvl 34 is like 2 lvl 17s, otherwise high levels are just too expensive...
With mysuggestion they count slightly more, but not that much...
So say with 340 points in a battle you could have 10 lvl 34, 11 lvl 30, or 17 lvl 20. A few more, but not as much as in your suggestion.
With more points, the effects would be proportional
EDIT: Some numbers.
40 lvl 34: 1680 points
40 lvl 30: 1440 points
45 lvl 30: 1620 points
50 lvl 27: 1650 points
60 lvl 22: 1680 points
EDIT2: Tweak. Since 1 lvl 30 is not worth 30 lvl 1s, add 6 to each person's level (number of starting attributes). This way 1 lvl 30 (36) would be like 5 lvl 1 (5*7=35), more reasonable. Changing the numbers above