So, my push rods are the 5/16 with a .116 wall thickness. I can get by with adding a .060 shim to my current valve springs and then may get 3/8" push rods in .145 wall thickness just to be safe.
There is upside and zero downside to running the biggest, thickest pushrods you can cram in. If the exhaust ones are even bigger, that is better still.
I had 7/16 on the exhaust and 3/8 on the intake of a W5 deal.