Griffiths, aka Pelican member kuehl has a lot of information on his web site.
AIR CONDITIONING HELP HOME PAGE,a/c,ac,air,air conditioning,barrier hose,Behr,Bosch,compressor,compressors,condensers, condenser,condensors,drier,driers,dryers,evaporato r,evaporators,freon,Griffiths,improvements,Kuehl,N ippondenso,Porsche,r12,r134a,San
POE 100 esther is his preferred oil to use- mixes with old AC oil unable to flush out in the expansion valve and evaporator.
quote " is this a DIY job?"
Yes with the tools, guages, electronic leak detector or dye, seals and a decent leak down pump--NOT a cheapy venturi Harbor Freight pump.
You can also improve the cooling of R134a with a "dual tube condenser".
Griffiths sells one and v2Rocket_aka944 has built a few.
J_AZ