dude get a SRW 14 bolt and swap dually hubs and get some cheap 8 lug rims from summit and call it good. shave it and go discs , keep the 4.10s and weld it and call it done.
rehear the front to 4.10 at that point.
30-spline 60 shafts are the same size as the 44 shafts you are breaking now. Full-floating is better however. If it were me, I'd do it once and go to 35-spline chromos. Bore the spindles or find a better 60.
"14 bolt shafts are 30 spline but are cut differently than most other axles. They are ~1.625" and are most comperable to 37 spline dana axles. They do neck down but the way they do may be the genius in their design: having some give before simply snapping."
I guess you could regear the 14bolt to 3.55 if you really want to keep the 30? you might be the first wheeler in history to want to actually gear a 14 bolt to 3.55 for rock crawling instead of 5.XXX something.
or if you are only breaking shafts grab some chromos for the rear from a vendor and see how long they last.