[pHaestus]

My opinion is that one is much less likely to end up with a partially bled system (with air in the radiator) using a reservoir plumbed into the inlet of the pump. I think the performance loss from air in the rad is a lot larger than from any difference in flow rate between a t line and a reservoir. The only way I was ever satisfied with filling loops using a T was when I didn't connect the radiator in the case until after filling it. Then I could shake it and the wb and putz with the loop until it was really air-free.