My centrifuge supply drum is semi-upflow. Its set up as an upflow with the incoming pipe going all the way to the bottom, and a drain valve on the bottom, however I'm not taking my good oil from the top of the drum like a normal upflow. I have the outlet fitting welded in 1/3 up from the bottom.
To answer your question, it works pretty good, but I always like to let the oil settle in it for a few days before I start 'fuging it.