"FWIW, on cheap bikes we'd install the cups with a bench vise and a sacrificial strip of wood or plastic."

Gah. Someone once told me they used a C clamp and two blocks of wood to install a HS. Sounds like it would work fine, but on the 62cm frames I ride that'd be one heck of a c-clamp (or bench vise). Needless to say, I've never used this c-clamp method, and cannot speak as to how well it works. Since I now have a press, I'll stick to that.

Again, the key is to take your time. And watch the cups as they go in. I also hold the frame up to the light once done and check at the edge between the head tube and cup to make sure it is seated properly, no matter the method I use.