12boy, my Brompton came with a 50 X 13 so the GI were approx 82.4, 61.8 and 46.4 according to Sheldon's calculator which is close enough to the 3 speed standard numbers in the 'official' gearing chart that I'm sure any variances are due to slightly different interpretations of the 349 wheel's diameter with tires.

Thanks for the tip on the 130 BCD Sugino crank. I've been hunting for one that works since the 5 I have in my parts bin didn't have the correct offset. Do you have a pic of yours so that I have an image to refer to when searching for the Sugino?