It looks like you're well on the way to having some excellent quality cables. That hydraulic crimper sounds interesting- - - - -mine does the same thing with a 3-lb. hammer with the crimper sitting on my anvil. Soldering a well-crimped connector is sort of like using a belt and suspenders to hold your pants up- - - - -overkill, but effective! The disconnect can be located in either cable, as long as it interrupts the current flow. I always attach the ground cable to the block or bellhousing, since the starter is by far the heaviest current draw item. Then I run smaller-gauge ground cables to the frame, body, and bed to assure the lights and other accessories are well-grounded. There's no such thing as having too many grounds. If you're running a DC generator, be very sure the base of the voltage regulator is well-grounded to the generator housing. Lots of charging system woes can be traced to poor grounding between the generator and regulator.
Have fun! Cranking a hotrod flathead V8 with 11:1 compression in a 47 Mercury convertible in the early 1960's was my introduction to diagnosing 6V starting problems, but I was lucky that my father was one of the best auto electrical specialists in Nashville Tennessee!
Jerry
