You are lucky to have recieved that lens mount with your enlarger! I'm still looking for the Durst equivelant ( LARATUB ) to use an 80mm on my Durst. I'd probably just set it at F8 or F11 and keep it there.
I have a mount almost that deep to use a 25mm on my 4x5 enlarger. But my 25mm is a very tiny lens and I can get my fingers around the aperture ring.