[ECUPirate]

I'm just guessing, but I'd say T-lines aren't worth a damn. In my system, when the pump is on, the bubbles became suspended in the solution... they went from being large air bubbles to very small bubbles that made the water look cloudy. When I let the system rest, they would settle out of solution in random places. With the pump on, and the air dissolved into the solution, a T-line is not going to be very effective. The bubbles would just be sucked past the tee.
At the top of my system, I made a resevoir out of 1" PVC pipe. (I wish I had a camera). I'm using 1/2 ID silicon tubing elsewhere. A given length of the 1/2" silicon would have about 1/4 the volume of the same length of 1" pipe. This gives the air a brief chance to settle. So, the water passes up into the res, and into the main chamber (a 1" Tee). In this area, I places a good bit of the blue filter that came with the Eheim pump. This serves to help filter out the bubbles as they pass through. Then, the water exits at the bottom. The exit is about 6" below the intake, giving ample time for the air to rise.
All told, my system took about 1.5-2 hrs to bleed.