Completed cutting the second driving axle just before leaving for work this morning, so I now have both driving wheelsets test-mounted and gauged to 19.85mm back-to-back. Was a bit unhandy with the piercing saw on the second set, so there are a few scratches on the tyre faces
I think L-shaped spacers from n/s or brass provide more support than the square ones.
What I could do with is more frame depth in the area of the driving wheels, particularly over the hornblocks, to provide a bit more strength to the topline of the frames. I know the original design which persists to this day was the most expedient way of catering for most builders, which is fine and would have worked well for the many people who bought and built these kits over the course of two decades-plus; I just wanted to see if I could develop it a bit further.
I am looking at assembling the footplate/ cabsides / valances as the kit stipulates, and then assembling and test-fitting the cab interior (which the instructions say is for 21mm gauge anyway - grand ). Putting these sub-assemblies together will hopefully show me how much room I've got for the chassis, and whether I can add material to strengthen the latter whilst I install the CSB suspension system.
The bogie also looks as though it can tolerate a change in assembly.