On my setup I just use a 2 way manual switchbox(
BBox ), which is mounted under the slideout keyboard shelf. Granded that the amiga doesnt automaticaly swap screenmodes for me. But the switch is closer to me than when I have to pick the joypad up from the floor (where it always seems to be these days :-) )I did try the tvcard for using pal screens on the gfx screen but to be honest I didnt like it one bit and an happy enough using the switchbox and there is the option of one of these
Automatic Monitor Switchboxwhich im guessing would just be used in the same way as a manual version.
Well thats my two pennys:-D