THe hilux diff is the go here for sure, not just ratios.

MY advice isn't 'new' or revolutionary - do it slowly, small section at a time and leave to cool, then weld the 'opposite' side for about the same amount. Getting the 'dowel' pieces machined on a lathe to ensure it is all 'straight' is the hard part (and it's not 'that' hard either).

Once you've done yours, serious suggestion - consider weighing up what you'd want to be paid to do one for someone else. And if you come to that $$ figure, advertise the option. You never know, it might be the start of a decent little side earner for you (or anyone else).