Forum:I don't really get Geth (ME1 and ME2 spoilers)

I was wondering if anyone could correct me if I say something wrong?

The Geth in ME1 were the Heretics and were influenced by Sovereign. Which is probably why they fight and make war with pretty much everyone who defies them or the Reapers. In ME2 however, there are 2 types of Geth. The Heretics and the "true" Geth. It was stated the true Geth are in the majority. However, we've never seen them except for Legion. Where are they? I guess somewhere far away from civilization or the Quarian homeplanet?

Also, in Legion's loyalty mission, we can choose to rewrite or destroy the Heretics. If we choose to rewrite them, does that mean all the Geth are on our side in Mass Effect 3?

Thanks in advance.