I ALWAYS suggest 1st disassembly at 4 hours, JUST IN CASE. If the devcon flows in underneath the trigger or magazine , its easier to get them apart now instead of later. You can always start over again if necessary, but once its together its VERY hard to take it apart with epoxy.
My 2 cents and experience. I've done about 20 so far. And yes, I have ALMOST epoxied everything together more than once.
Prep, prep, prep and pray for a little luck as well. You can always clean up a messy bedding job with a dremel and sanding drum.
Larry
Tinkerer