I just realized I forgot to post up my results after finishing this AC project. Short story is the duster gas (aka. R152A or HFC-152A) works about as well in my restored FC A/C system as the old R12 did.
The 1st reman compressor I got was probably damaged in shipping, in that the mag clutch would sometimes stay engaged even after it was de-energized. The company I bought it from (see previous posts) replaced it under warranty, but that meant I had to R&R the compressor, evacuate/vacuum the system & recharge it again. Good thing R152A is dirt cheap - $11 for a 4 pack of 10oz cans at Walmart.
The step by step procedure I used for evacuating & charging the system with R152A is within in the first 40 or so posts here from the other forum:
https://www.rx7club.com/1st-gen-arch...gerant-997918/
The best result I got was about 7*C (= 44.6*F) temperature from the center vents at max cooling. According to the link, it should take in about 2x full 10oz cans of duster gas, but I couldn't get the system to ingest more than maybe 1-1/2 cans. Not sure why, as I followed all the tips suggested in the link to get the last can in. So perhaps my system is slightly under charged, or perhaps the new expansion valve I got, which *I THINK* is calibrated for R12, being it's an OEM replacement, might not be optimal for using R152A.
For my busted auxiliary E-fan, I found a nice 10" universal fan on Ebay for about $18 that I was able to easily adapt to fit the stock e-fan bracket. No more noise & crazy vibes when the fan kicks in.
Anyway, I'm happy with it!