Sand down the area, lots of glue and put the patch on, apply some pressure for a few minutes without getting your fingers stuck to it then leave it to dry. Mount and pump to pressure for a few hours, overnight if not in a rush. Then let air out and add sealant as per usual.
Patching the inside of a tubeless tyre that wont hold a plug . Whats the best technique with one of those velox expensive repair kits ?.