John Cutler
I am not surprised I am confused. The current Alan Gibson catalogue for the standard 1/8″ axle driving wheel 4866ST shows it as being for the LMS Stanier 2-6-4T with 5’6″ wheels, 17 spokes, Pin Between and a 13″ crankthrow. This is incorrect and Colin Seymour has told me he will try and sort out for the next catalogue update.
In the absence of a 5’6″ wheel with the correct 13″ crankthrow, I would use the standard EMGS conversion wheelset, which is for the MR Flatiron.