Ringo
Simplex, Senator, Nubian, Utile etc are the same size, if you get the "standard" - there's also a smaller "medium". They're about 11 3/4" x 10 1/2". The difference is/was the leaves. The Utile used to come with linen-hinged leaves, the Nubian comes with black leaves, although the current Nubian binders aren't up to the standard of the old. If you're buying new, you might take a look at these - SG size, but made by Lighthouse
http://www.worldstamps.co.uk/Salisb...nd_75_LeavesIn second-hand, look out also for Prangnell-Rapkin, which are, I'd say, better than SG.
Geoff