Apparently the Pirelli is the only one that always works properly on a non-tubeless rim.
Why are you worried about a non-tubless rim ? Just say tubed rim.....
your not running a modern trials so G.A.F......
YOU can run tubes in the tubless anyway, and on Dt you wont notice the differance infact i have found the tubless cases runs better with the tubes, i think the walls or bead is differant somehow but they stand up taller, or should i say dont fold over as low on the wall, when you push them down to 8psi and run around radius corner.
You watch even a 250F on a Dt track and you can see the tyre sits almost at right angle as its comes off the contact patch, you'd swear it was about to peel the tyre off, there is that much flex in trials tyres.....