How to unfollow people effectively on Twitter?

I have never done twitter before and I read a lot of threads on how to get followers.

My goal is to build 1 legit twitter account that would drive traffic to my site. I know I need to follow the followers of popular accounts in my niche.

I have an old account (over a year old) but I don't know if I can change it's name. I can also create a new account. My question is: how many people can I follow with new account and with an old account/day. And even more important: how many and when do I unfollow people? I have read that if you unfollow only people not following back then your account will get banned. But if I follow people following me back then they might unfollow me also. How can I keep a ratio of more people following me than I am following?

I hope somebody can answer these questions (mostly about unfollowing).

1) Start with 500 following in a day
2) Unfollow up to a 1k in a day 4-7 days after following
3) Unfollowing people that doesn't follow back will get you banned!!! I don't know where you have read but it doesn't make sense and I don't think that this is true.

Anyway find it out what works best for you, and repeat te process.

Regarding your questions about the Twitter, read:

https://support.twitter.com/articles/66885-why-can-t-i-follow-people
https://support.twitter.com/articles/68916-following-rules-and-best-practices