dude your should know this about GFX and scan doublers with the toaster.
the toaster does not work with most scan doublers, the only card that I could get to output SD and FF signal is the picassoIV. Any other gfx card and you need and extra monitor for the toaster. Ifcourse you still need a program and preview monitor.
another thing ppl forget is that the toaster is not zorro, it uses a video slot. the 4000T is the only amiga that has 2x video slots - hence the only one that you can add the GFX card in addition to the toaster.
good luck!