lower shroud tang location on mast

[Megunticook]

I'm prepping a new mast for my TySenior. On the original mast, the tangs for the lower shrouds were attached to the lower throughbolt that holds the spreaders. I notice on the factory diagram, however, that there's a separate throughbolt slightly below the spreaders that fastens the shrouds to the mast. Just wondering if I should go with the factory diagram or the original mast. Seems like drilling one less hole in the mast is a good thing. But maybe there's a valid engineering/design reason for having the lower shrouds fully separated from the spreader assembly.

Also, I need to replace the sheave for the jib halyard. Anybody recommend a quality replacement product?

Hoping to be in the water before Memorial Day weekend! Only one sailboat in Camden Harbor right now, floats are starting to go in. Still pretty cold here, we have the woodstove going this morning.