Easier to leave the manifold-HP hose in the car. If the car is on ramps, there is plenty of room to install the seal washers after the new R4 is in. But wait until the R4 is back on before oiling it by pouring down the top of the suction tube (disconnect nut up high). However, I agree w/ the plan to replace the HP hose and get rid of the silly run up the R side of the engine and the bracket that bolts to the top of the upper oil pan. I did so, running straight over to the condenser and bending the factory fitting at the condenser down to match. That will free up space and places to trap gunk. You will then find changing the turbo and air cleaner oil drain stub O-rings easy and adjusting the alternator (no EGR also helps a lot). BTW, the AC hose fittings all have circumferential O-rings so don't go crazy tightening the nuts. All you need is enough so they don't unscrew themselves under vibration.

If replacing hose (wise, I did), I recall the suction hose is -12 size and HP hose is -10. Use only "barrier" hose since less leakage and better compatibility w/ non R-12 refrigerants. If you want smaller OD, buy "reduced barrier" size. An AC hose crimper makes factory-looking crimps on new ferrules (I did), but Oeticker step-less ear clamps would look nice too and only require "nail puller" pliers to crimp. I bought all on ebay. You might pay $120 for a used ferrule crimper kit but can sell for $120 when done.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans