Silo question(s): fret size? To shim or not to shim?

I just picked up an old silo with a floyd for 850.00. It was listed as “mint”, but unfortunately it does need a little tlc. My only real issue with it is the fretwear which will necessitate at minimum a level, but more likely a refret. Fortunately, I got what I think is a decent price for a guitar that’s hard to find.

So the question is, what size fretwire gets me closest to original spec?

Also, the action is a tad high the farther up the neck I go. Would shimming address this? If so, would the shim cover the entire neck pocket, or just the portion closest to the bridge?

Thanks!