An Excel spreadsheet showing dimension conversions for gauge 1 models to 1/32nd or 10mm:ft.  Look up the full size dimension in column A and read off the scale dimension in column F or H.  For any new dimensions, insert a new row, type in the full size dimension and drag and drop the formulae from the row above.  Once you have downloaded the file into your  spreadsheet application, you can modify your copy as you wish.