Seeing all that wiring would make me want to get a untouched factory loom and start from scratch.

 

Lol. Haven’t seen all of it yet. Believe it can be repaired with “ minimal” headache.

 

As long as the plugs on each end have the correct color-coded wiring, they can easily be spliced back together to stock. The first pic in Post #99 shows how a 'spider' was used to bind the Trailing and Leading Ignition together,

 

Yep, that's why I can't set trailing timing. We're working on the wiring every day. Many more splices and cut wires

 

Fixed it! Thanks to many hours and patience donated by GSLSEforme here on the board, including his diagnosing my new timing light as defective from 445 miles away over the telephone. Much rewiring to correct prev owner's errors.
The main problem turned out to be a bad tps. After I finally ran down the correct one for the car (that's another story to follow), it runs better than ever.

Here's a tps caveat. If you need to replace a GSL SE tps, order it from a rotary specialist like Atkins, Mazdatrix etc.The other parts houses on the internet have an error in the database used by 90% of them that lists the wrong tps for the GSL SE. So don't order a tps "for an 84 or 85 GSL SE" You will receive the 86-88 tps. The correct Mazda part # is N236-18-911. Order it by the part # only. Took me 2 weeks of grief to learn this.

Thanks to all who helped me here.
John