I assume (I might be wrong here...) that the CV64/3D scandoubler switch works more or less like this:
Signal on gfx-card input: Gfx-card selected for output
No signal on gfx-card input: AGA selected for output
Sounds nice & simple, but the CV-PPC/BV-PPC doesn't switch the output off when inactive, unlike other gfx-cards.
Which leaves the BMon switch in combination with a Scanmagic as a pretty good solution, nice&internally mounted, but still operated by a pushing a button.
