I don't use any exploits. Once again you have a weird idea. It's simply too expensive to drive to all the mines each time i switch - crafting recipes are too expensive this year, so rather than use all that SEC, i use multiple miners, one at a time. That's not an exploit.
If anything is an exploit, it's using a dog to carry all that weight. Poor dog. Myself, i use a cow so it goes pretty fast. So we're on the same track on how to mine efficiently.
I do not believe you've tried to open "every lock in the game". Have you been to the Glow? Like i said, two of those safes are really tough, tougher than skill 200 will handle.
Now if you are telling me there is no advantage whatsoever to a salesman with Barter any higher than 200, or a party leader with Speech any higher than 200, then THAT info changes those two builds for me, big-time. If i can confirm that, that's gold, but guess what: i'll still have 1 char for each use.
More on fighter builds: most of the potential combinations would be worthless to test. But why would you use your LSW fighter to fire rockets? I mean, you could, but if you want a rocket guy, then choose the right perks. So that's two count-em-two big guns fighters. Now about a year from now, when all my plans are fully fleshed out and i'm known as the wasteland's safest car dealer (lol), i might level up a spelunker who uses an improved flamethrower. He'll have the Pyromaniac perks. That's 3 big guns fighters! Hahahaha!