I like the ingenuity and effectiveness in this design. I used a simplified version (two separate main sheets, port and starboard) on Rosebud when I removed the traveler. Each sheet connected to a pad eye on the cabin top with a snap shackle. On a broad reach or run, I could take the off sheet and move it forward as a preventer.

On your system, what is the advantage of taking the two lines forward along the boom, down to the deck, and back to the cockpit? Why not just take them down to the rail again to double rail blocks? It would take a little more line but the single sheet would be more powerful.