Steve, I am at work now, so I can't measure my two Beseler 45s (one with the Ilford MG600 head, one with the Condenser Head), but an observation:
When I use the one with the Ilford MG600 head, with 35mm, I am often at minimum extension - so much so that I have considered making a recessed lensboard for my 50mm lens. I rarely find that I need to use the maximum bellows extension, since I rarely print really small, and when I do, it is usually not with 4x5 negs, so I can always get a smaller image with a more convenient enlarger head height by using a longer lens.
You can calculate the maximum bellows extension required too, if the distance between the negative and the optical center of the lens is B, and the distance between the center of the lens and the easel is E, then the magnification is E/B and if the focal length of your lens is F, then when in focus, 1/B + 1/E = 1/F all of which means that if the smallest print you want to make is a 1:1 size print, then the maximum bellows extension is approx 2X the lens focal length. The shortest bellows extension would come about with an infinite sized print, at which point the bellows extension is equal to the lens focal length.