I agree that you wouldn't want to "T" the return line into the draw tube line. That would create a negative pressure on the return line and it might potentially create pressure imbalance issues within the IP.
If your using a 55 gallon drum, or similar, you could drill & tap the bung cap to facilitate installing a draw tube and separate return line fitting. Of course the draw tube would go to about 1"-2" off bottom and the return line only has to penetrate the fitting enough to allow any return fuel to flow inside.
