A few tips from AC work on my fleet of 7 vehicles:
RV-2 is a heavy beast, but dependable. Sanden is the best replacement and used by most hot-rodders. SD7 is latest greatest (more pistons, smoother). Come in various sizes, w/ H15 (15 cc?) most common. All have same front-side bolt pattern and most have 2-groove pulley though I have seen 1 groove ones. H14 is same length. H13 is 1" shorter, if pressed for space. Used in Civics, but might suffice in a C-body up north. Many rear heads available ($20 ebay). You can swap them easy. Most rodders use top O-ring fittings (#8 suction, #6 discharge). No need for a surge bottle like the RV-2 used. Some heads have a port for a pressure relief valve (PRV, ~$8 ebay, ~290 psig), which can keep the compressor from slipping the clutch and melting it on a hot day (happened to me when 108F in Sacramento). Shop for all AC parts on ebay in the winter, when I have bought a new Sanden for $50. My Newport came with an after-market York compressor (Sears, Western Auto, etc did many retro-fits in the 1960-70's). It is about as small and light as a Sanden so satisfied.
I have the Master-cool crimper (maybe $120 used ebay). You can also buy hose and ferrules on ebay. Buy "barrier hose", which has a liner to lessen leakage thru the rubber (mandatory for R-134A). I prefer "reduced barrier" for a smaller OD, especially for suction hoses. There are add-on crimp jaws (pricey) but I found the next smaller size is often perfect, and indeed Master-cool states that for some sizes. I also fabb'ed oil cooler hoses and coolant hoses for my other cars (M-B & minivans) using the crimper. When done, I'll sell it for about what I paid. You could also use Oeticker stepless ear clamps for a professional look (ebay). No need for the special crimp pliers since cheap "nail puller" pliers work or probably the PEX crimp pliers at Home Depot would also.
A parallel-flow condenser is 30% more efficient and ~$50 for a "universal" on ebay. C-bodies have room to get a large one for better efficiency. If a non-factory AC car, cheapest is to use an under-dash "knee-knocker" which came on my Newport. It is long and thin. New ones are $110 on ebay or $50 used. They have an integral expansion valve and anti-ice switch, so just connect 12 VDC and 2 hoses. Go thru the firewall w/ bulkhead O-ring fittings, as most rodders use.
Re refrigerant, R-134A is being outlawed (bad greenhouse gas), which has long been true in Europe. I have used Duracool (hyrdocarbon) since 1997 in my Newport and now in all my vehicles (even 2002 T&C). Read all the FUD spread by AC shops and decide the risk for yourself. No fires in millions of car using it. A bottle feels empty (6 oz) so carrying a newspaper in the car is more scary, plus you would smell any leak (Mercapton added). I even poured some liquid on the concrete and lit it to see how scary. It barely burned, like candle wax (must boil first). I also use PAO 68 oil since more efficient and doesn't absorb moisture (like PAG) to cause internal corrosion. Mixes with all prior oils and works with any refrigerant (at least HC, Freon, R-134A, don't know about R-1234yf).
