8-3/4 sure grip unit

I have a 489 sure grip CONE STYLE unit with 323 gears. I disassembled the unit from the case to remove the center button, but how do you line the splines back up between the cones and the unit so the axle will slide back in? It looks like this needs to be done before I can tighten the case half bolts back down.
I have the unit on my bench, and I don't want to take my car apart until this is ready to go back in. I wish I had a spare set of axles to use, but I don't. Is there any other way??
Any help is appreciated.

George