MTTs - not good for building roll. Play small buyins as a treat now and then. Expect -ROI.

SNGs - perfectly good for building roll. Play at your roll AND comfort level. If you single table and you put 500ish on starts, I would start with the turbo 15s looking to move to 20s or 25 Turbos pretty quickly if you're up.

Once you get above 1k, mix in more MTTs.

On your "Will I stop playing to win"... you don't really expect anyone to answer that but you?