I have a few docks anchored to the bottom of my second monitor but every time I restart my computer they show up on the wrong monitor. I quit and launch DT and it go back to where I want it. Is there something I can set to force them to stay in place?
Try the "Lock Position" setting in the Advanced section of the Dock Options. If that doesn't work, delay opening DragThing until the restart has finished - it's likely the second monitor isn't being seen when DragThing starts.