play a couple of games with the set up you have. When the match is over, look at how much quanta is left. Do this about 10-15 times.
If you end up with tons of quanta left(in the 40s/50s) and very often, then you can reduce the amount by 1. Now try again 10-15 times. Depending on the outcome, adjust the amount accordingly. If you have tons of quanta left over at the end of the game, it means you drew a few too many pillars/towers instead of other useful cards. You should aim for the amount of left over quanta to be in the teens.
Have you played starcraft? In that game, one strives to use all their resources, and any left over is considered bad. Same concept can be applied here.
I play a lot of people who draw like 6 pillars/towers in the first hand, which is VERY bad. It means the deck is not balance. first hand should be like 2-4 pillars/towers.
good luck! 8)