On tallit slippage

Recently we received an inquiry from a customer concerned about tallit slipping.

I prefer a full size tallit and I am 5’8″ tall (173cm I think). I am quite broad across the shoulder and my current tallit always slips off my shoulders. My current slippery tallit is 130cm long and 178cm wide. I think the reason it falls off my shoulders is because it is not wide enough. Could that be the case?
Tashbetz nonslip tallit
Tashbetz with black stripes. Note the box-weave.

In recent years many tallit makers have developed non-slip tallit fabrics. They have more texture, which give them a nice supple feel and creates more friction. On our webstore, all of the Tashbetz and Bareket are made using this type of nonslip tallit fabric.

I told him a size 60 should fit well, and that he can expect it to drape down in back to mid-thigh.
Tallit slippage is a common issue but not an exact science. I am willing to entertain his hypothesis, but from my experience, less tallit actually stays on your shoulders better. I know a broad-shouldered tallit dealer whose ownpersonal  tallit is quite narrow, yet he claims it stays in place really well. His theory is that lightweight material stays put better, which makes sense to me. If this theory eventually gains traction, I might try to write up a formula to express it. Something like this:
Less Tallit = Less Slippage