Valve spring limitations vs Cam selection

Thanks Mark. Earlier in the week someone on FABO posted a link to EngineLabs. They have some very interesting information there and also have a newsletter that I subscribed to. They don't seem to be pushing anything even though they do have advertisers (someone's gotta pay for it...right?). Anyway...looky what I got today.
Taking It For A Spin: Why Are Some Cranks Externally Balanced?

edit.....I think they offer a lot of good information especially for a novice like myself.