-
For what it is worth and from my personal experience, open tubulars have more supple walls so much so they are pretty much flat when one side of the bead is mounted on the rim.
Lovely ride though and wouldn't switch them out for anything else.
That said, have seen tubes being pinched many a times by those who claim know what they're doing.
I run some on my commuter (challenge not vittoria) and I love them!
Are open tubulars not just good quality clinchers with Kevlar beads?