My first vacuum frame was a millington set up for offset plates. I got it with my Olec, so I decided to make the best of it. It's possible, but it entailed cutting the metal frame out from underneath the bottom so that the glass wouldn't be obstructed when the lamp was shining up from the bottom, removing the glass from the top of the frame and placing it on the lower part.
With a flip top, it seems like it would be more complicated since the blanket would still technically be on the bottom, does there need to be something to prevent the screen just hanging in the blanket? As in a board that is 2-3 inches away from the glass?