A/C questions on '66 Valiant 100

See this post for info on the various compressors and refrigerants, and see this post for factual information on hydrocarbon refrigerants (BillGrissom, you're incorrectly informed. European-market cars use R134a and there's a schedule for its replacement in new cars with fully sealed/hermetic CO2 systems; isobutane and other hydrocarbon refrigerants are not used.)