Yes, azcat, I did exactly this about 3 months ago. I love it. Getting rid of the old halyard in front of the mast, with its noisy banging around is a relief.
Actually, after I bought the whole setup from the dealer, I relaized I had the masthead piece already. So I actually have a spare masthead piece, if you want.
You need three thing to make it work :
1. Masthead casting with sheave.
2. masthead hook
3. halyard ring/shackle.
Don't worry about the forces, it's designed for it. You're right, that stupid little fork this on the front of the mast is by far the weakest part of the system, you'd be getting rid of it for something much stronger.

Jim
5.7 Wind over Water