I had good success patching a 3/8" sidewall cut in a WTB Resolute. I superglued the cut and used a large automotive tubeless patch from Autozone which was thicker than an inner tube patch but more flexible. It bonded so well you could see the black patch through the gum sidewalls. Be very careful sanding/roughing the inside so as not to cut through the threads. I have also used a inner tube patch on a smaller cut, which worked well.