Goldmember
I'll SHow You How To Stunt - UTVUnderground Approv

Ive got my rad in the same place. We did a trick aluminum overflow bottle under the bed tins, with just the cap showing. Looks and works great. Big improvement over having he stock one zip tied next to the rad. I can shoot a pic if you want. I got the overflow bottle from Kartek.
the radiator will suck coolant up the hose and into te radiator if needed. its more for expansion of the coolant not as much for putting it back into the radiator.
This makes things more clear for me. I bought a unit from Latest Rage which has the cage mount clamp on it with both the overflow drain and 1/4npt fitting on the bottom. Screw on fill cap ontop. Will this work mounted beneath the radiator??