Radiator overflow tank - Do you use it? Why? Mine is overflooding

[Hindsight]

Myself and many others delete the rad expansion tank. Just cap off the barb at the radiator (use a clamp too) and ensure the pressure rating on your REAR cap (at the engine) is lower than the one on the radiator. Ideally, you run a small 1/4 or 5/16 hose from top of rad to rear reservoir, and rear reservoir is highest point in cooling system.

Also, something is wrong if your front reservoir is filling while you fill coolant from rear. I bet you have the bleeder hose going into it instead of the hose that comes off the radiator fill neck under the radiator cap.....