What is the recommend # of people you follow per day on your Instagram account?
You should be able to follow up to 150 / 200 without too much issue 
yes, keep that under 150 max, and if your account is new I would say 30 per day until your account is warmed up correctly then you can increase that value slowly
Start slowly, with 30-40 follows per day and then slowly increase them, but never go over 200.