If I understand the question, The best solution is to put something
in for an axle that is straight.

...... If you don't want to buy another axle from the junk yard, get another piece of straight material,...... and after carefull measuring...... weld on the end plates and any other fittings to be sure the end plates are squared to the axle. TreeKiller could weld it for you. And as long as you are making a new axle, make it from stronger stuff than the material that got easily bent.
-----------------------------
Sliding the axle back/forward on one side to compensate for it being bent, is not worth the trade off of lengthening/shortening the distance between hub centers on the car's left side versus the car's right side....and the axle would still bent.....and the car would pull slightly to one side...and
would not handle properly.....

and BTW.....how much does a new axle cost?-Bob