There are many factors like how active you are in other actions and the age of the account. 60 follows twice a day with min 1-hour difference works great for me if I have a very good target (wherever I am following). And I can also do the same number of unfollows. Basically, it varies and usually, the best practice is to do a little several times a day rather than all at once. Also, an important role plays how many accounts you have on the device. I usually have a lot of issues with 4 accounts per ip but it goes muuuuuch smoother with 3 accounts.