I’d change your approach slightly - rather than just opening the viewer of a given operator, I’d find the operator, and then use it with a window COMP. A window COMP has a handful of other handles for window placement, size, borders, etc. that will ultimately give you more flexibility.
thanks Matt, will look into that. The Window COMP seems a bit over the top but will give it a go.
I was hoping that the openViewer Class had some hidden gems in there to help me out!