He likes to tinker and build his own setups, though.
Have to say to O.P., I don't really follow any of your logic hence why I haven't bothered responding properly, but if you just seek validation for buying an ultegra groupset, just buy one. At least it's what you want to do. It does seem like you want to be able to walk around and say "I've got an ultegra groupset". Won't make you any faster; apparently might make the cycling experience more enjoyable.
It doesn't look like you'll get much technical validation of the concept on this forum. I would go 105 and Merlin Cycles are doing them for £299 right now.
For wheels, spend £250 and you're going to get an improvement over the stock Allez wheels. So it boils down to aesthetics really as none of the off-the-peg wheelsets in that price range will be massively better than any other. Shop around for bargains, those Pro-Lites are about the lightest in the budget if you get them now from
Chain Reaction Cycles. Up to you if you took the chance with the Campagnolo freehub. You sound like you know what you're doing mechanically.
Wiggle were doing Campag Zonda with a shimano freehub for £285 until the end of today. I spent £170 and got Vision Team 30s. For an extra £135 I could've got Vision T30s... Thing is with wheels their characteristics are hard to experience and compare until you've bought and fitted them.