It's pretty ridiculous, but it can be done.
My advise, get 2 Rbands and loop them around, then slide you arms in for a couple hundred lb backpack.
For everything else go 1 arm, 1 arm deads are pretty rough if you havent tried them. Worry about the other arm later if you REALLY need to cut, though I might do some squeezing grip work here and there since your other arm will mainly be doing grip stuff.
Static (isometric) work could be good too, if you can handle it. Things like squeezing and holding the arch in your back while on a bench or flexing your muscles on your other arm, like rear delt, scap squeezes, anything that doesnt hurt, just flex the hell out of it to help keep some balance.