Basically, it's just a big elastic band. Where you want to position your handgun is up to you. I wear mine just slightly ahead of my right hip. You also determine how high you want it to ride.
I am amply proportioned myself, and have had no trouble with slippage or roll.
Just a minor correction on the sweat through factor; the only part of the firearm that seems to get moist is the upper rear slide area which isn't covered by the material. I routinely wipe my gun down with a silicone cloth when I get home and haven't had any problems.