To heel... or not to heel...
One caution about heeling your boat at the dock. Use the swiveling spinnaker block halyard. Sideways pull on the in-line main or jib halyard block is not good, and if you still have the old wire halyard, you will kink the wire...
Other than that, you can heel 'er down until the masthead is at nose level, or until the dock you attached the halyard to tears out its cleat... "Quite Dramatic", as you can imagine.
Actually, I have seen an owner of a lightweight Martin 24 heel it down this way to work on the masthead, with success.
As to the idea of going up the spar, you can do it IF you keep the boat *vertical*. A friend once did this to clear a jammed halyard on our old Ranger 20, between races! That was 23 years ago, and we were all a bit younger and stronger...
(Damned wire jumped out of the sheave -- "wire is evil"!!)
Not to take all the drama out of the problem, but why don't you lower the mast -- don't these do that by using either the boom or pole as a gin pole, depending on whether it lowers aft or forward? I used to do that, every other year or so, for maint., on our former Niagara 26. It lowered aft, with the spinn pole for a gin pole, and took two of us to manage the guys ... spar was 34 feet long... What with set-up time, it took about 2 hours to do it. Not fun, but not dramatic either.
Best,
Loren