A/C pressures

I put 60 psi (@ 80F) low side at a fast idle in my 02 Silverado work truck, dont have high side fitting. It's got a leak they wont fix so I just fill with cheap Propane (poor mans R290!) and it cools down to 35F out the vents on high. R134 is almost as expensive per oz as Johnny Walker Blue out here in CA so I just let it leak good 'ol environmentally safe propane. Yeah, I've heard how 'unsafe' it is but most of us are driving around ~20 gallons of gas 2 inches from exhaust pipes and some is pressurized 55 psi inches from 500F exhaust manifolds. 60 PSI will last me 2 months before its unable to kick the compressor on.