Hi Scott,
I have a J29 and this Winter my rigger found the exact same vertical cracking through the rivet holes of both spreader bases.
I am now in the middle of the very same decision making. And because we share the exact same issue, I would be curious which way you have choosen to go?
Have you had any luck getting through to Rig-Rite?
Charleston Spar purchased Kenyon and is the leading supplier of J24 masts. They have told me that they have the extrusion for the J29 mast section and can supply me with a new mast. You may give them a try.
-Rob
