I got tired of replacing crappy made Marshall and other hoses (about 6 in a short period of time). One or two leaked between the acme nut and crimped hose fitting and the rest leaked because of bad hose crimps not holding up.
I bought new green acme nuts with 1/4 NPT male threads. I had new hoses made at an industrial hose supplier here. They had propane rated hose that was 350 psi like the original hoses I was replacing. The hoses have crimped female NPT connections on one end and crimped 37 degree flared female swivel nut connections on the other end. I replaced the adapters on the regulator with 37 degree flared male x 1/4 NPT male adapters.
Best thing I ever did for propane hoses. No more junk hoses and could have save a lot of money replacing hoses. I could keep the hoses as short as possible and once I connected the hoses to the propane cylinders and got the natural curve of the hose turned to line up to the regulator connections I connected and tightened the 37 degree swivel nuts to the regulator adapters.
No twist I the hose or bending the hose against the natural curve of the hose.
Make sure to get the green acme connectors. Black are for low flow (gas grills, single appliances), green are medium flow (several appliances such as in travel trailers) and red are for very high flow (