John Sexton includes a session on unsharp masking in his two advanced darkroom workshops. The method he teaches is much simpler than that taught by Howard Bond and seems to work well. I don't believe that the utility of unsharp masking has anything to do with how you focus. Also, you actually don't need any spacer material. The thickness of the film alone will create enough space to make the mask unsharp. work. At least this is what Howard Bond concluded in the second of his "Photo Techniques" articles on unsharp masking. I always found the spacer to be a pain - dust, scratches, etc. appeared on it with regularity. Since Howard's second article appeared I've stopped using a spacer and the unsharp masks seem fine without it.