I have the same radiator and the same overflow tank. No more coolant on the floor!
To install the overflow tank, I needed a short length of 1" angle to make it fit. Overflow tank holes on one leg of the angle. Radiator mount holes on the other leg.
I plugged the transmission cooler holes with ear plugs. I haven't looked to see if they are still there.
Do you have any photos you're willing to share? I'm still trying to figure out how I'm going to mount it
