Before I get into an elaborate discussion of masking techniques, I guess the first thing of a pertinant nature is to find out what film format you are using?
I could tell you how to do unsharp masking via email if that would help. That type of masking requires no registration equipment on the enlarger. However, sharp masking requires very precise repeatability and film registration.
I wrote an article in the May-June PhotoVision magazine that discusses one application of sharp masking. That magazine is a sponsor of this site and I am sure that they have a past issue that you could purchase if you are interested. Additionally I am in the process of writing two additional articles that will cover photographing in high contrast situations (above 12 zones) and also an article that will cover masking techniques in printing of negatives incorporating extreme brightness ratios. I am not sure of the date of publication of these.
If you will advise as to your film format, that would help a great deal on what and how I may benefit you.
Best regards, Donald Miller