...I do have some deck eyes directly outboard of the mast's turnbuckle:
View attachment 152074
I could easily slip a hook from a rachet strap through that. I'll keep you guys updated. Plan on trying again this weekend after the repairs.
I assume you meant to write that the strap eyes are Outboard of the mast tabernacle (not mast turnbuckle”)
There are two problems with using those eye for anchoring the baby stays. First, they aren’t tall enough to be on the same axis as the pivot bolt in the mast. They appear to be at least an inch lower than the bolt hole in the bottom of the mast. If the baby stays are snug enough to prevent sway when the mast is down, they will be too tight when the mast is up.
Secondly, the eyes are attached with a wood screw into the deck. That’s fine for resisting a shear force (perpendicular to the axis of the fastener), but not a vertical force. The fasteners for the anchor point for the baby stays should be through bolted, with fender washers on the backside to resist a tensile load pulling up and parallel to the fastener.
I’d recommend that you install some small u bolts or beefy strap eyes in line with the hole through the mast, horizontally and verticallly.
Personally, I’d use wire cables for the lateral bridles, it stretches less. Straps and rope are very stretchy. Dyneema has a lot of initial construction stretch. It gets fluffy (loosely braided) every time you disconnect it from a load and that makes it noticeably too short at first and too loose after it’s loaded for a few seconds.
I’d also recommend putting some turnbuckles in the wire baby stays. That makes it easy to fine tune the length of the baby stays so you can get the length right once and keep that length.
Judy