I have tested several trans and converters with hoses to the coolers.
The system I used that worked for me on a pretty much stock engine and 200 4R was Parker 801-Plus (-6 size) with push lok fittings. I used radiator clamps to additionally secure the hose to the fittings. Required by some sanctioning bodies.
The reason for my post is to caution users to know what your trans out to cooler pressures and temps are.
On a 820 rwhp, 3950# car, PI 3400 measured stall, 5-disc converter, 200 4R, in tank OEM cooler; I logged 125psi out pressure and a max oil temp of 245*F and 2.2 gpm at the strip. 801-Plus hose is near this as max specs go. Logging was pressure transducers, thermocouples and electro-magnetic flow meter. The trans was a highly modified full manual unit. On the 801-Plus look for flexibility and color change. Note that the SS braided hose has higher specs than the 801.
On my pro mod, glide trans car. I found the SS braided trans out hose had melted the braid impression into a plastic hose bracket. I put the instrumentation on the car; the results were a surprise. The converter builder was also surprised. The pressure out was 150 psi and 340*F oil to the coolers. I now use AN-8 teflon lined SS braided hose to the coolers, and SS braided on the return. Most suppliers have these products.
Another good reason to use synthetic fluids.
I changed converter builders; now, I have 290*F output oil temp. Also quicker.