We also have a Nor'Sea 27 and use the boom to raise & lower our mast. We towed it back to Az. in the US from Guaymas, Mexico and Ed & Ellen helped us. There DVD is a GREAT place to start. You don't need all kinds of extra stuff to do it! Nor'Sea owners have been doing this for quite some time.
You can see us lower our mast in Mexico in our Youtube video at;
at about 3 min 40 seconds into the video. NOTE, the video is in 3D, but you can just turn that off using the settings.
You can see raising a mast on another Nor'Sea 27 on our Youtube at;
At the Havasu Pocket Cruisers Convention on Lake Havasu. Raising starts about 7 min in. This video is NOT 3D