http://www.ziplink.net/users/lester/FLR.html
Update 5 Feb 2009 I have installed the focal reducer and it was no problem to get back to 1600mm (the correct ratio) from 1900mm without the tube (optics in the old housing) stars look tight and field curvature isn't much of an issue. Makes for a much nicer installation with less mass away from the center of rotation.