Regarding TH-700 years, I think '92 and newer use electronic shifting so you may want to stay away from that. '82-'86 (I think) used a weaker forward sprag which was beefed up in later years. An earlier TH-700 can be retrofitted with the stronger sprag. If you don't plan on abusing the trans, then the weaker sprag should be just fine. I have an '82 TH-700 behind a warm 350 in my '57 chev hardtop and I haven't had any problems with the weaker sprag.
Regarding wiring the TCC, as earlier mentioned you may be able to utilize a valve body switch like the 4th clutch switch. There were many different wiring configurations for the TH-700, some may have the proper configuration and it is just a matter of getting power to the right pin. I activate the TCC in my '57 with a small toggle switch and power is routed through the 4th clutch switch. The 4th clutch switch is closed when in OD (4th gear). I wired the TH-700 TCC in my 55.1 with one exception...power goes through a brake switch. When the brake pedal is depressed, the switch opens and the TCC unlocks, regardless of what gear it is in.
If you are doing your own rebuild, make sure you check out the pressure switches that you will be using. I have come across a few that leaked.
