First I should say that I have never done a cyanotype, but will as soon as the chemistry is in my mail.
I use 4x5" and maybe feel that it may be a bit to small for cyanotype.
I wonder if anyone have used the enlarger but changed the bulb to a UV-bulb?
Does it work? Do you have a link to the bulb?
I should add that I use my camera as an enlarger so I have no problem changing the bulb.