There are honestly so many variables, and everyone will tell you something different. What skill or bot? private script? Clean IP? How many accounts per IP?
I've had bots last for close to a month in p2p. Using the method you are talking about I got 80+ wcing and flethcing, over 60 smith and 75 mining on a main. It did eventually get banned. Sounds like you are trying to make a main. F2P is shit, you'll get banned quick.