The supply line is gravity-fed, so no real pressure there, right?
The return line is pressurized by the scavenge side of the oil pump. The scavenge rotor is smaller and this generates less pressure than the supply side, and teh return oil path is relatively unrestricted, so I'd guess your max pressure in the return would be half or less of your oil gallery pressure.
Seen many oil lines re-done with standard hose clamps and also the fancy covered ones. I'd guess you're fine so long as you use wide enough clamps, properly sized hose, and your ends are in good shape.
mystic_1