You said from the T on the main tanks... Make sure your feed lines and vent lines are the same length, and your clunk lines and clunks sit about the same place in the tanks if they are parallel. sometimes saddle tanks just dont transfer evently, but you must watch out for that because of one dries up faster than the other, you can induce air and flame out. I recentlly ran my hanson trap to see how long it would keep fueling. It kept the turbine running all the way down below 1/2 full... good confidence builder..

keep troubleshooting. If the tanks are plumbed in serial, its easier to trouble shoot,, but for saddle tanks, cant do that... some guys put a small header tank below saddle tanks to feed them too... I see that around a bit instead of parallel tanks feeding directly into a uat.

I plan to do that on my Flash because the main tank doesn't feed the best below 1/3. I also plan to do that on my F-16 which has saddle tanks..