The Effetto Mariposa Carogna works tape exceptionally well and is simple to use. I've been using it since it came out. Lennard Zinn now says that's all he uses on his tubulars. There is no way it's going to let the tire off the rim without a fight if you apply it properly (which is simple to do). I can change a tubular as fast as or faster than I can change a tube in my clinchers.
You can run "tubeless tubulars" if you use Tufo tubulars. Nice tires, no inner tube. Put in sealant and it will be a rare thing if you get a flat prior to the tire wearing out. You can plug the tire if it does get a hole that at the sealant won't close just like all the tubeless clinchers out there.
If you need to carry a spare or want a tire inexpensive tire, Yellow Jersey Bike Shop in Madison WI (has online presence too) used to sell three for $50. That's what I carry for a spare if I think I need a spare.
J.