Finally the decision has been made.

I don't think it would hurt. But.......and this is simply MY personal opinion here, so take it for what it's worth, but I don't like Teflon seals on the street. I prefer the Viton rubber. I've just had better luck with them. That's just my personal opinion, like I said. Teflon seals are geared more towards race oriented engines. I would even rather run a standard old umbrella rubber seal on the street instead of Teflon. Course, opinions vary. I do agree though, you should probably cut the guides down a little.
I do have a question about the original seals are they supposed to stay locked down on the guides or do they move up and down with the valve? Cause I noticed during disassembly that some was locked down tight as could be on the guide and others where up on the valve towards the retainer