WHat do you think of these back space measurements?

[JSharpe]

I have a 71' Camaro that I have am almost ready to get new wheels for. I am going to run a 255/40-18 in the front on a 18x8. For the rear I am going to run a 295/35-19 ona 19x10. I have the tires and mocked them up in the rear. They are snug, but I think they will fit. I wanted to get input on the backspace measurements that I have come up with. For the rear I am looking at 6" of back space and for the front I am looking at 4-7/8" or 5" of back space. What do you guys think? Thanks, JS