Thanks. Kinda pricey. Any after market locations?
Any custom sized boom fitting will be pricey. Most major modern spar manufacturers sell a similar fitting custom sized to fit their various booms. The trick is to find one that fits the groove. It doesn’t necessarily need to be an articulation bale. It could be stationary.
Remember also, that you will have to remove the end cap on the boom to install a slider.
If you don’t want to spend the money for s sliding eyestrap, consider adapting an ordinary forged stainless steel eyestrap that will fit inside the groove on the underside of the boom. You’ll need a rather large one to accommodate the reefing line diameter. Get one that has well rounded edges that will not chafe the rope. Install it using a rivet (I’d use an AL rivet for this, not Stainless)or a machine screw, and be sure to use a galvanic isolator such as Tefgel.
Eye Straps
shop.sailboatowners.com