I've never reattached a tab before but if I were doing it with any type of bonding material, I would drill small holes on both pieces so that the "plastex"/ "fiberglass jelly" will bond all the way through.
I'm in the process of painting a bike and I repaired two small holes on a fairing. I drilled four small holes around the hole to be fixed so that the patched area would be stronger. It came out very strong and after I paint you won't be able to tell they were even there. Not sure if that helps?????