hi dan

i used to use a 90mm lens on my gvII all the time.
if you want to use it on THAT camera you need a recessed board.
you put the front standard all the way to the end of the rail,
and then move the rear standard pretty close to it, until you get an image
on the glass ... you shouldn't have any problem.
you put the front standard way-up so the end of the rail won't be in the image ..

the recessed boards for your GVII look like this

it will work on your crown as well, the front standard needs to be in the "box" and the bed down ( so it isn't in the image )

good luck!