904 Questions

Hey guys been reading a lot about rebuilding my 904 and have jumped in deep. So I have a later model with a 5 clutch front drum. Measuring the dry stack of clutches I get a clearance of only .020 with a flat snap ring. I realize this is way too tight and I need more like .070 I asked the transmission shop down the road that pressed in all my bushings and they said they don't mill pressure plates, they would mill the piston which I thought was strange, .050 off the piston seems like a lot. What would you guys do?

Thanks,

Phil