I may have access to R12.
 

Assuming leak test comes out good, is there any aversion to using this? I understand it can’t be vented and would likely work better with the sanden 575.

it is what the original system was designed for, i'd have no trouble using it

so far the best upgrade is to add a condenser fan, with the stock setup you can add a relay and use the compressor to trigger it.

With clutch fan 100% operational,this is an unnecessary mod. Have had both on several cars and while the aux fan increases airflow at low speeds,oe fan works as well without extra amp draw of electric fan and associated wiring,relay and larger alternator needed to power it.
The fact that fan runs whenever compressor is engaged is a waste at anything over 15 mph.

A trinary switch can be added to system to refine operation of fan only as needed. Yet more equipment...

Cooling fan,clutch,shroud system in 1st gen really well designed and works well,shame so many are replaced for electric fans- that often don’t function as well.

I also agree that you will have no issues using R12. That stuff is as scarce as hen's teeth these days!

You may want to consider using R152a as its basically the same cooling wise as R12 and considerably friendlier to the environment when it leaks. Otherwise its what the system is designed for, go for it!

Still using R12
 

In 2008 I traded my SE wheels for a complete working A/C system then reinstalled it with new seals, a new filter/dryer, and had it evacuated and charged with R12 by a shop. Other than recently adjusting the BAC to compensate the idle it still works just fine.

https://cimg0.ibsrv.net/gimg/www.rx7...cce9100db3.jpg