Thanks, @Zubail - should anyone else be reading this thread in the future I can confirm that Ben’s advice is spot on.
I did some long climbs yesterday and they generally worked out well - 4H Part Time, Offroad Plus mode on, long press on the TC button to reduce assistances, and manual on the gear shifter.
I was finding that upshifts at circa 4500-5000 rpm on the run in was good, prompt downshifts at 3000-3500 rpm in the run uphill as rpm’s decayed, modulate the throttle from mid to full application, left/right steering to find grip as you go.
A few observations of the car’s behaviour:
1.) Important to feather the throttle to get timely downshifts. I think the Jeep is a little funny about a downshift with 100% throttle being held.
2.) It has a soft limiter for RPM, so when you hit redline it will aggressively limit you to that power setting. I don’t think it backs off, but you will immediately stop accelerating and that loss of momentum is going to hurt how well you do in the next gear up (basically if you hit the limiter you need to seriously consider as to whether you can keep climbing or need to be ready to bail).
3.) With some practice you can use your ear to time the gear shifts. My exhaust has an extremely noticeable note change coming down through 3000 rpm.
All this was done with the Tazor Mini removed - this may have been doing something strange with the transfer case previously.
I suspect that 4H Auto might do even better for getting speed initially (it’s basically an AWD system in that mode - and might help you generate more speed on a run in) - however the trade off is that the auto system can only react to conditions, it can’t anticipate, and that might cost you some performance later.