That's a great picture! Looks like everyone is on a "Bahamian moor" to keep bows into the swell. I think the snatch block part of the rig is one of those things that can really only be tested in a great amount of steady wind so that the forces are continual. It seems to make sense that if a block intersects the anchor rode anywhere in front of the bow that it will slide to a point of equilibrium when tightened; form a triangle with intersect, bow attachment, and cockpit attachment as the corners. By changing the length of the cockpit line, the angle of the boat relative to the wind would change. Geometrically, it works in theory.
Boat design, of course has a lot to do with whether any of the idea works. It's likely that boats that heave-to easily will probably work better with this "enhanced heaving-to."
Would be nice to actually deploy the sea anchor on a snotty day but the prospect of trying to get it back in and the clean-up and repacking have always squelched the idea. If actually used, I'd try to sit it out until the seas calmed back down to retrieve it.
Alberg 35: With a philosophical flourish Cato throws himself upon his sword; I quietly take to the ship.