Nice job meeting the challenges of EXTRA LARGE work. I didn't usually need to figure out how to keep stained glasswork from falling apart, but I have had my share of cabinet jobs that did need to be just so. It can be a royal PIA to keep really large pieces flat, and square as you put them together. My best tip is a worktable, that is dead flat (big honking torsion box deal), and at least 5' x 10', but larger can often be a blessing. Of course it helps if you can keep the darn thing cleared of "necessary" items. There you need a rolling cart you can drag over to the big table. And the biggest of course is you need the room to keep all of that ready to go. Small shops may be a shorter walk, but that is the only plus they bring to big jobs. Miles of empty space come in nicely when doing them, prep, assembly, finishing, all need their own space. If you don't have it, the juggling alone can defeat a lesser Man.