tre5
+1y
I would start with 550 psi on the accumulators.
Cylinders, you could use a power ball or a heim joint on the bottom. At the top, just weld in a doughnut where the shock came through and then drill the shock opening out to the size of the cylinder. Cut yourself a sleeve to go over the cylinder. That sleeve will ride against the collar on the cylinder and the frame of the car.
Always use steel fittings, do not use brass!!! Stick with 3/8" NPT and #6 JIC if you're just looking to go up and down... no hopping.
For hardline use seamless stainless steel. 3/8" X .049 is what I use with #6 JIC (37 degree) nuts and sleeves.