Whooee! That takes me back in time to ordering my first , non borrowed guitar. 1978 I ordered a "GLOBAL" guitar and 10w amp from the Sears catalog. The guitar came with a gig bag that had snaps on the tail end, so they broke and it got scratched the first week.
Your guitar has a lot of after market decoration added to it . How to wire it? You were correct about the slider switches, they were just on-off, but a couple on-off-on switches would give you phase switching which I always thought would be a plus for that axe.
I am honestly surprised if any of the original plastic knobs on the tuners are still there after all these years. Forget about playing in tune with others as well, the non compensated bar bridges were usually off enough to be irritating to anyone. This is a perfect guitar to retrofit aftermarket parts to. Nothing really worked well, and it gave me my first lessons in luthiery. Mine wound up being my second guitar as an open tuning for slide guitar till I traded it for some fuzz pedal. Pop open the pickups for a real surprise!
The woodwork and everything else is fine, but I've only recently got into the wiring side. Collecting quite a few diagrams as I need them, and learning as I go on, but I can't find how to do this combo anywhere. I've tried Seymore Duncan and a couple of others, so any pointers in the right direction, or links, would be great.