Steve, it won't be the end of the world if you have to dimple the tubes a little to get plug clearance. It's an imperfect world.

As far as roller rockers, I strongly urge you to use brand name products that have a good reputation such as Crane, Comp Cams, Isky, Harland Sharp, etc. I have heard some horror stories about the cheapo rockers. You get what you pay for.