I'd have to go outside and look at the kit mounted to my M35A2C to see how high the lights should be. There are actually a couple of standard pin locations for adjusting the altitude of the lights, one position for non-use "storage", another for when in use on a 2.5 ton truck and one for when in use on a 5 ton truck... Bassically, you have a larger diameter pipe that is clamped to the back of the cab using u-bolts with a smaller diameter pipe sliding inside it to adjust the height with the cables running inside the pipe sections...
When using one light, put it on the driver's side so you get increased visibility both with vehicles approaching from the front and rear and to minimize confusion with lights mounted on the shoulder (school zone signs or steep grade warnings that have a warning beacon on them for instance). Also, if you happen to have a gun ring mounted, putting the light on the driver's side keeps it away from the gunner...
A couple photos of the dual light kit used on the M35's (the "M35 convoy light kit) that I snagged off TnJ Murray's and Ordnance Unlimited's websites show that they have a lot of pieces to them, more than just a pole with a light...
The suggestion to fabricate a light from the pole mount setup that Saturn has available is a good one, especially if you can't source the full kit or don't need it to be "perfect" and/or only want one light. It also keeps you from having to source extra switches and wire if you got a big kit and used it to mount a single light on two trucks (or having spare parts to sell if you only installed a single light on a single truck).
