Might I suggest trying them in an inconspicuous place first so as to make sure they will not scratch.
I purchased the Zaino recommended Cannon Fieldcrest towels, cut the ends off and all, and they still left fine scratches which I now have to clear up.
I'm going to give Groit's a call. I've seen some of their stuff. Hopefully their towels will be better.
If you get a chance, post a response here with you findings on the Royal Velvet towels. I'd be willing to give those a try too it indeed they do not leave fine scratches.
Matt