Best way to build a bankroll ?

[XTR1000]

Do you reckon it would be better to hit hte micro stakes cash game

Maybe. As GatorJH said, if your feeling confident with your SNG game its not a bad way to build a BR there. Many here started out like that and switched to cash games later.

with a push/fold strategy waiting for the nuts to come

100% no. Although micros can be beat with a fairly nitty strategy, playing push-or-fold is bad. It will hurt your learning progress and you´re missing a ton of money.