Yes - I would look for good quality blankets - smooth, without harsh stitching that could become a problem.
My original post shows the flooring - it is cleaned regularly so not overly concerned with debris that could catch on the blankets and scrape while sliding to reposition the speakers.
All in all, it's a low-cost 'test' solution - if it works, great - if not...
Is anyone on the forum familiar with Herbie's Audio Lab? They sell gliders, sound isolation disks, etc. - anyone use their products? Good? Bad? Neutral?