You also get a epoxy to fix hard to repair weapons so it would be stupid to do it as the last thing in the game. perhaps do it around level 20.
If you're level twenty surely you should have max Repair anyway? Suppose it depends which weapons you're using, but I've never had a problem with weapon condition whether concentrating on Energy, Small or Big Gun category. Alien Blaster, and other other Alien weapons might need it, but Wolfgang repairs to a decent degree. I've never used an Epoxy tube. Not even to test it. lol
I would also do point lookout then you start getting problems with the very tough broken steel enemies as it has to perks who boost the effect from automatic weapons. It would probably unbalance the game to do it to early.
What's the second Perk? Superior Defender increases damage output but only if you're standing still. Ghoul Ecology helps with Reavers but the benefits against regular Ghouls are marginal because Ghouls are so weak anyway. I don't see how it can unbalance anything. It's hard to come by a challenge early in the game, Point Lookout provides a decent one for low level characters. IMO