I use only Gallagher double insulated (inner insulation is red) wire in old garden hose buried under gates. I would put each wire in a separate hose. No need to run the ground wire in a hose unless it's rocky.  Also make a knife cut in the hose at a low point so water can drain out. Water will get into any hose or conduit you use. Bury it deep. So far no problems. Oldest gate opening is about 13 years old.

Why 2 hot wires?? One good hot wire in a hose and one ground to one charger should be plenty unless you have 2 separate chargers for some reason. don't run a hot wire and a ground wire inside the same hose or conduit. The drain is important.