Just have it match based on the stronger of the two in every aspect*, then if some team have a huge disparity, they will pretty much never win. Much easier implementation then hard limit, as defining an exact limit is complicated.

By stronger of every aspect I mean it can be a mix.

For example lv 80 70k power w/ 200 pts team with lv 85 65k power with 150 pt, it would be matched as lv 85 70k power w/ 200 pt