I have not used a B in decades, but as I recall and like the Ds the B should shoot to the floor but turning the unit 180 degrees then rotating the enlarger head so it projects over the baselaod and enlarger stand. As already mentioned Omega made XL frames which will project to a 16X20 but you need to make sure you have the ceiling height for it. If you plan on printing 16X20 you may want to consider a Bessler 23c or find a B with the XL frame.