Choosing the right cam

How do you come up with those number though?

It's really just from a lot of personal experience with different combo's and research from others with similar setup's.

I make a lot of recommendations just from years of seeing things that work and things that don't.

I've never claimed to be any kind of expert, and I hope most take my thoughts as just from someone that has had a hand in some builds, and just makes suggestions to get people thinking.