"double the compression on the mast"
Are you sure about that?
i'm thinking that the down haul pressure on the mast will stay the same no matter how you hold the head of the sail at the top of the mast.
My dad's Shark had a small wire winch at the base of the mast to raise the sail and hold it up.
The Super Cat 20 had a wire halyard with loops swaged into it and a hook at the bottom of the mast. The second loop was to reef.
You need a beefy, well attached mast head fitting that can support full downhaul pressure and a halyard with minimum stretch. Many mast head turning blocks are only designed to take the pressure of pulling the sail up and could break from 8:1 downhaul pressure since normally, the halyard lock takes over once the sail is up.