Right then… just as an update…. let out all the air in both chambers…
went to 88 psi in +ve and 80 -ve, was too soft…
Back up to 105 in +ve and 100 -ve, with about 2/3 rebound, and they're spot on – proper plush over big stuff, and sock up the small bumps nicely without lots of sag.
Interesting that the settings are almost identical to what they were before emptying the chambers