Another exhaust size question

[Mayfield]

Just wanted see what everyone's thought was.
5.3 with cam & LT with 3" collector.
So I originally was going to run 2.5" piping, but all the local exhaust shops around here only have the crush bend style benders not mandrel. Closest one I can find is about 5 hours away, that's just not feasible.

So now I'm thinking of going with 3" since it's not going to be a true 3" all the way through. I don't have easy access to a welder to fab my own. I'm also going with a H-pipe.

So what would you do, original plan of 2.5" or go 3" because of the crush bends?
I know I'm probably over thinking this, but I don't want it to be too restrictive, or go to big cause I need some back pressure.
Some guidance would be great lol. Thanks