home fabricated down and y-pipes?

Has anyone fabricated their own pipes from the manifolds on?

I have a 1966 Barracuda with stock 273 - it has some pretty crusty down pipes... and needs the rest of the exhaust as well. I have access to a large quantity of 1.5, 2, 2.5 and 3" stainless tubing in .065" wall thickness, and plenty of 90 and 45 degree elbows. Oh, can also tig weld...

Stock down tubes look to be 1.75" ID, with the rest 2". Is there any benefit to going to 2" for the down pipes? I understand there are some clearance issues with the early A bodies, but feel confident I can form some of the tubing to fit.

Any input is appreciated.

E.