Nevermind...found the info.
Nikonusa says that the Monarch UCC 50mm, Monarch Gold 50mm, and the Monarch Gold 56mm all have 95% light transmission. If that is the case, then why would I want to go from a UCC to a gold? Will the 30mm tube make that much of a difference? I guess I don't understand what the 95% light transmission means. 95% of what?
If I decide on the Gold, I'm going to go ahead and get the 56mm for only 50 bucks more. So I'm basically looking at a $200 difference. Not forgetting that Cabelas has the 56mm gold listed for $800!