The HDPF is 4mm, from Nuttalls, as was the 3mm standard density neoprene.
The neoprene section is from COH Baines.
The fitting may be fiddly because the gap between the lock casting and the timber frame is variable. If I do this job on the Plus 4, I may have to use aluminium instead of the HDPF because its a lot tighter. Aluminium will work, and will look OK when leather covered.
