how hard is it to separate the hubs for the process of putting new spokes in also best way to line up holes for the press operation back together thanks
Take a look at these two documents from the FunProjects website:
Wheel Assembly Press
Wheel Drilling Guide
I assume we're talking about your 1921 hack, which means steel felloes. If you're going to install new spokes, I expect that means the old ones are bad enough that they're loose enough for easy removal. Just set the wheel on the floor with blocks under it to support the spokes and drive the hub out with a wood drift and a BFH.
You drill the bolt holes after the new spokes are installed. Here's a video showing assembly with the Regan press. Be sure you pay attention to the notes about what's wrong in the video.