Tubulars really aren't that hard to stretch, glue, and mount. Anyone with even minor mechanical skills can do it easily. You can carry a folded lightweight track tubular tire in your jersey as a spare that would be adequate to get you home if you flat. The double flat thing is a problem though unless you carry two spares and that starts to get a little silly. Do you tend to get a lot of flats?

Beware that good tubular tires are quite expensive and may or may not be repairable. You could be looking at $100 to fix a flat by buying a new tire/glue/brushes/tape/etc. unless you're ambitious enough to take the thing apart and patch the inner tube and then suture it back up.

Knocking a pound and a half off the weight of your wheelset is pretty significant though, and for $500 it sounds like a good deal. Just keep your clinchers too just in case...