Thanks for the confirmation that cleats on the side decks will work, I'll rig them up over the winter.
As for the lowers, what I have in mind is some Dynema rope tied to the mast just above the gooseneck, down through a block fixed to the shroud chainplates and then back to the mast just below deck level via two cascades. This is then led down the mast and tied off to a single block, along with it's partner coming from the opposite side. A control line passes through the block, down to a couple of turning blocks at the mast foot and then up to cleats on the side deck near the shroud chainplates. All adds up to 8:1 purchase.
As for the lowers, what I have in mind is some Dynema rope tied to the mast just above the gooseneck, down through a block fixed to the shroud chainplates and then back to the mast just below deck level via two cascades. This is then led down the mast and tied off to a single block, along with it's partner coming from the opposite side. A control line passes through the block, down to a couple of turning blocks at the mast foot and then up to cleats on the side deck near the shroud chainplates. All adds up to 8:1 purchase.