Thanks Tom, that'll get me partly there. Right now I've got a 210 Rodagon on it but only with a cone that gets me to 12" as the smallest enlargement. It's a royal pain to break out the 11x14 paper and trays every time I want to proof anything. Come to think of it, I may just improvise a longer cone for the 210 with the number you provide. I made a cone for my 4x5 enlarger out of 4" PVC pipe and a toilet flange (not used) -- it ain't pretty but gets the job done.