Dennis:
"is there a secret way to raise it up into place?"
yeah....the best way we've found is to use a Sears Motorcycle jack or equivalent - that way the jack will raise the engine level without letting it mofve around. It looks like this:
http://www.sears.com/shc/s/p_10153_12605_00950190000P
Maybe you can borrow one from a friend for an afternoon?? It works LOTS better than a regular, roll around floor jack, as the engine stays level and the transmission input shaft should slide right into the clutch disk (with the usual amount of jiggling and turning of the crank to get the splines to line up).
"The Webers make it too wide to simply raise straight up.
And I'm REAL hesitant to unbolt a carb - afraid I'll put it out of adjustment."
Well, you're right - there isn't a whole lot of clearance between the frame rails and the carbs, so something's gotta give. Personally, I usually remove the entire intake manifold/carb assembly as a unit on each side and then just replace it once the engine's in there. Either stuff a rag into the intake ports on the head or use some soft rubber balls. Many people remove just the carbs and then the tops of the manifolds just squeak past. Either way works. If you are careful in removal and re-installation then nothing should get out of adjustment. After the engine's in you should perform a carb sync anyway, so don't worry about it.
While you can re-use the carb base or manifold base gaskets, I usually put on a new set, just to be sure they'll be OK.
Take your time, good luck and keep us posted on progress.....
gn