Paul, You're dealing with such tremendous pressures here, all you need
to do is put a little soap on the barbed fitting & push the line on---
it will conform to the barbs enough that it won't blow off until you
reach 0.5Mach.--leave the clamps off.

Actually I already tried that solution, but the clamps are not the
problem. If I push the tube all the way on the fitting it is
amazingly hard to pull the tube off. I can usually do it outside
the airplane, but not lying on my back reaching up under the
instrument panel. I end up just cutting the tubes off, but there
is a limited number of times I can do that before the tubes will
get too short. Perhaps if I don't push the tube on all the way ...
But it would be a fine line. Or perhaps Tygon isn't the right
stuff, and another tubing type would make it easier? Still I
think a fancier fitting might be appropriate.

~Paul