68RNR

Hey all!
Time for the first of many questions I am sure I will post here.
I hate to pose another wheel and tyre question, and I have done plenty of research already with regards to this so please be patient.

I want to fit 295/50/15 tyres onto the rear of my 68 roadrunner. I am told these will fit fine with a 15x10 rim with 5.5" backspace.

Issue I have is that I want to put centerline convo pro's on, and the only ones I can get have a 5" backspace. Will this be enough to stop the tyre fouling on the outer guard??

Also I am going to run a 215/60/15 front on a 15x6 rim with 3 3/8" backspace. Will this be appropriate? Will it fill the guard enough or do I need less backspace?

Thanks!