I'm currently building out a manifold for this as well and it seems generally, six of one half dozen of the other. You can run the Qtank on its own pump, T into your existing return line with a flow control valve feeding the Qtank, manifold your return and have dedicated ports.
Will it be the same height as the DT? IMHO, the easiest way is to place the FT a little below the DT. Allow the water to drain from the DT to the FT and then to the sump. Gravity is your friend! No extra pump that way - just a little extra PVC.