Another trick I saw people on another forum do is:

1)apply g2b (and in your case the 2nd glue also)
2)lightly spray some alchy on head
3)place unit
4)take bandana and tightly wrap it down for 15-30min.

apparently this produced a very firm bond. perhaps the alchy gets rid of all the water content and leaves a really secure bond? not sure on the details on why it works well.