I checked three sources for your R-12 capacity for your car and found the following:
1.) 2.2 lbs
2.) 34 oz.
3.) 38 oz.

This would give an avg. amount of ~ 36oz. of R-12. Using 85% to 90% of this figure to arrive at the approx. R-134a amount comes to approx. 30 oz.

If you used approximately two 12oz. cans you have 22-23 oz. of R-134a in yor system. This is a fairly significant undercharge on this size system. Weight charging, on a retrofit, isn't that reliable though, and some gauge pressures at 1500-2000 rpm would tell us charge status. I'd like about 220psi/30-35psi on an 80ºF day @1500-2000 rpm with windows open and CCU set at "min" and blower on high.

I'm NOT saying that an undercharge accounts for your symptoms, but I'd start off there, before moving down the diagnostic tree. Undercharged systems trigger some oddball protective "faults" quite often. FWIW Good luck

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)