flat tappet vs roller

I'm definately not a Hemi guy... But.. I would be concerned with a solid roller spring pressure so I'd be thinking about a custom solid roller that can use a milder spring. The pushrods, rockers and valves in hemis are heaaavvvy, and there's more friction than a wedge. So I think I'd be looking that way. I like flat tappets, but to get big power the flat tappet will need to be larger, and then the springs, etc etc etc. A milder solid roller will last a while without the lifters needing repair. Also, look into GOOD lifters. Bullet has some coming out with pressurized oil feeding the wheel. That is the best way. Not cheap, but long lived.