The guy who said about doing the straps that way is right. You can have them loose like that but still have the grip feel secure and if you fall it's all good. You can just drop your poles easily too and have them dangle. I used to do them with my hand going down through the loop and tighten the strap. The I fell one day and tore my UCL. And when I got it checked out I found out I'd dislocated it too and chipped ab one. Then when I got it check up 6 weeks later they x-rayed my "good" thumb as a reference and it turns out I had a chipped bone in there too from earlier in the winter.
Anyway, for protection I now wear a splint on the thumb that had the ligament tear that a physio made for me. It was made from a sheet of thermoplastic moulded around me so it's a perfect fit, nice and slim for under my glove and still strong. It feels really secure. I wouldn't bother with anything off the shelf.