I did do this when I built the engine, there was minimal loss on the exhaust valve only. Intake came out as advertised on the cam card. So geometry must’ve been pretty good. Got the roller tip centred well on the valve tip etc…
I don’t think I’ll lengthen the p’rods. I can convert to ball/ball rods & cup adjusters then use off the shelf p’rods. Oil through the rods, then block the oil squirter for the adjuster in the rocker. Just weighing it all up atm.