I use a four spoke wood rimmed wheel on my +8 and find it much better than the original even on longer trips. No experience of the leather bound model.
I'm curious about the Mulberry bearings. I had a similar setup fitted by my local dealer and the steering became much lighter but the shimmy without damper blades on uneven surfaces was intolerable. When you fitted the Mulberry bearings did you remove the damper blades? I'm given to understand that fitting modified bearing sets without removing the blades does not make the steering lighter