I am really not seeing how it would make any difference other than having more pressure from having the coolant higher than the radiator. The coolant enters the radiator from the top and exits through the bottom so unless you run the entire radiator dry you won't suck in air and any air that enters the radiator will stay on top. You didn't leave the 't' in, did you? That plastic 't' probably won't do well over time.

Did you try it out after you back flushed the system?

Let me know when I can stop by manassas and see if your results can be duplicated. I am tired of freezing.