Safely following Twitter users

I've read a few different posts about it, but they seem to range.

Does anyone know roughly how many people it is safe to follow each day, or per hour, if there is a difference? I am using an account I do not plan to monetize directly, but rather promote my actual, personally created service.

Thanks for any help!

if the account is new do not follow more than 150-200 people..

once you get around 500 followers you can follow around 300-400 people

All accounts have an initial 2000 user follow limit. After 2 weeks of Tweetattack i've reached my 2000 user follow limit and I cannot follow any more.

I think i will have to run a few unfollow runs with tweetattack the next few days to unfollow users who haven't followed back. This will ensure my following to followers ratio readdresses itself.

Stats at mo are 2001 following with 1543 followers, so this ratio is obviously not letting me follow more.