I know what you mean, as fast as the domino goes, we always want it faster
One thing you can try on those legs is to make a little spacer from two pieces of scrap, one goes vertical, so it catches the end of the leg, the other goes horizontal long enough to establish the position of the domino fence, then just slap that on, snug the domi up to it and drill baby drill!
Also, you can gang up several legs and mark them when one pencil line if you have a good square or an mft.
For gluing, I have no silver bullets. I glue the tenons into one piece first, then attach the matching piece.
Maybe the best advice, though you might not like it, is always do a dry fit. You definintely don't want twenty wet tenons that aren't gonna fit.
Good luck and please post some pics!