I have done more research. The instructions advise to remove the opal screen if using the opal bulb. The intent was to use one or the other.

Base Board Footprint:

The M 600 baseboard is a little larger (15 1/2 x 19 1/2) than a Valoy baseboard. This is a very compact enlarger.

Without a color head/transformer it would be very easy to move and store.