I have a T-shirt quilt in my future (need to make a start soon) and frankly I'm dreading it. I have worked with a lot of different materials, but so far no Poly/nylon. If you are keen to tackle it...maybe buy a couple of second-hand shirts of the same material and do a few practice squares. You can then see the results for yourself and then decide if you are willing to go ahead and/or if she likes the finish before committing to the work. Sorry I can't be of more help...but I'm sure someone here may have tried it.