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.
I didn't and it worked fine, I'm sure letting it go tacky would work just as well if not better. From what I'd read what really matters is the quantity of glue, you need a decent-sized blob.
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.
Worked for me, YMMV.