DO NOT put any heavier rollers in, you will get much less acceleration and hill climbing (too low rpm), but you can put up to 2 grams lighter rollers in, which improves acceleration and hill climbing, but probably loose some top speed. Best is original weight or 1 gram less with roller weights.
Even with flat spots some roller weights usually still work pretty good. Don't forget, slider weight are flat too. CLEAN all surfaces e.g with acetone, that is important, but do not oil.