Daniel, you've got a great rig there. The Kydex sheath is a real plus with such a beast of a knife. Being a Panawal, it can take a lot of abuse.
You mentioned the vibration felt while chopping. This is something that's very obvious with my big AK Panawal. Heavy chopping with the wood grain and splitting are comfortable tasks, but cutting hard wood across the grain REALLY lights up the hand at the end of the handle. (it's a 2-hander) Like you, I've made some adjustments in the way I chop, and it's much better.
Not meaning to state the obvious here, the Panawal's full width tang gives great strength, but more shock comes along with it. The narrower spike tanged khukuris absorb lots of vibration, and I now understand the purpose of that design better. It may not be necessary, but the Panawal design seems to be great for prying and extreme abuse. I like having a khukuri that's so heavy duty it can't fail under any circumstances.
Having never destroyed a basic spike tanged khukuri (or any other style), I don't know what it takes to bend or break a tang or handle. What folks have said in old postings about the AK is that "you just can't bust 'em". So much more for the Panawal.
It would be interesting to hear experiences of direct comparisons between the average AK and Panawal of the same size.