The SR&RL Portlands and Hinkleys seemed to be subjected to multiple cab door configurations. The original short-sided forward portion with the fold-down seat looks the same as the original WW&F 2&3 cabs. Next came the sliding door arrangement, which seems really impractical with snow and ice, let alone the potential for getting pinched. It looks like they originally mounted the rear grab iron for the doorway on the sliding door. I wouldn't want to grab that on the fly! The last/ current arrangement seems pretty good. A little more fixed forward cab for shelter and a return to the swinging door. Also, the original short brass grab irons look cute, but the later, longer thin irons are more practical for crews.
All that said, #9 looks great! You folks really do things right!