OK, you guys are making this over complicated unnecessarily. I used the KISS principle on my 26M that has a rotating mast. In light winds the mast does not always rotate on its own, most times it is facing windward and one has to go forward and manually turn it to leeward. I simply ran two control lines aft to the cockpit. They run through two small harken blocks each side of the mast and are attached at the mast base plate along with my vang attachment. (your vang is quite high indeed) Each line, starboard and port start at the mast base with two harken blocks, the line runs through the blocks. One block is attached to the mast base while the other is anchored to the stantion base which on my boat is directly abeam of the mast. So the line starts with a knot to the stantion block then runs over to the block at the mast base, around the block, then back to the stantion block through the pulley then back to the cocpit where I have it cleated. Same arrangement starboard and port.
I can see clearly on your photo that you have a mast base with a tang on each side to attach the blocks, hopefully you have a stantion or some other means of attachment directly abeam of of those tangs. with a small harken block at each position you can run lines with 2:1 purchase between the blocks then aft to the cockpit and you have control both ways at your fingertips. Works hot dam on my 26M. It is also very inexpensive and easy to do, your only hurdle is an attachment point exactly & directly abeam of the mast base on each side of the boat like the 26M with the two mid stantions right there, very convenient.
