Larry,
I made just what you are thinking about a couple of years ago. Originally I tried using just a single block attached to the halyard. Too much effort (I'm not as strong as I used to be!). I then read about a professional rigger who uses a 3:1 arrangement. I copied his idea, and it has worked well. A single block with a becket is used on top (and hauled to the masthead with a halyard as you described). For the bottom block I use a single Harken ratcheting block. It takes very little force to hold myself in place with the ratcheting block, so resting on the way up is possible. I used 150' of 3/8 line. With a 5:1 purchase it would be even easier to haul myself up, but it would obviously require more line.

I am using a 4-part block and tackle with abt. 180ft of 5/16" rope. The lower block has a ratchet type sheave. Works very well for me.
Hans Treu
C36 #849

I thought of doing something like this, but my problem is that, being pretty short, if I ascend the mast in a bosun's chair I can't see over the top of the mast. I'd have to be standing up. With a block and tackle, this would make it even worse. So, I'm thinking of that mast mate. Any thoughts?

John,
I have the exact same problem. To solve it, I installed a pair of mast steps about 4' below the masthead. They are on each side of the mast, fold up when not in use, and allow me to step up and see everything on the top of the mast. I'm sure the hard core racers would cringe at the thought of adding about 2 pounds that high up, but it has worked very well for me.