I would SERIOUSLY consider doing the roller rockers now and go with a roller cam. I have heard of so many people having problems with flat tappet cam lifters that I don't think I would go that route. You understand that too. Lots of performance-oriented machine shops will not even build an engine with a flat tappet hydraulic cam. Evidently almost all hydraulic lifters nowadays come from China. All I know is what I have read and heard. BTW a well-known machine shop here will only build a complete engine if you go with a roller cam.