I don't know the answer to that since I don't have access to a Spintron. I talked to a few different sources and they recommended with 900 lbs open spring pressure to run a thick wall 7/16 pushrod.

The Smith Bros pushrods are probably in the $20 each range so they aren't too expensive. They are a straight wall 7/16 pushrod with a .120 wall.

You're correct on the expense. I've spent about $4000 to go from the flat tappet MM305 to this roller cam and that is with me doing a bunch of the machine work myself. It hasn't all been required though, I'm trying some new stuff out so I consider it more R&D than anything else.