Hey,what's your screenname? I'm grinding $3.50s and $7s atm.
About moving up,I'd recommend you to maybe mix in a few $7s into your $3.50 sessions,this might make you feel more comfortable with the higher buy ins and harder opposition.
$7s definitely have less random fishes,it's harder to get paid out.
The skill level of the regs is about the same.
About bankrollmanagement,I'm not sure since I'm not playing on my own roll (staking+coaching deal) but I guess 100 buy ins should be alright if you are able to move down in stakes quick enough if needed.
GL