Hi,
I've done this before, the axles were shorter on a sureqrip back then, but I did it by taking a the flanges of a later bolt in type axle and cutting the center out of them so all you have left is the ring with the bolt holes in it. they're about 1/8 to 3/16in thick, that's about how much shorter the axles were, then you use one on each side and then play around with the stock thin shims that come with a open rear to get the end play you need, around .008 total. I've got some stock thin shims if you need some more to play with. either that way or you have to cut the axles off. it will also move your brake drums out a like amount which shouldn't hurt as long as you don't have a rust ridge where the shoes don't run.
Russ