I rode a couple of hours today with the new handlebar/riser set up. It makes more of a difference than I thought!
The riding position is more leaning forward. This has three positive effects. It has resolved the 'numb tailbone' issue better than all the changes I made to the seat-foam. The handlebars are more stable, making for better handling, and I reckon I won't be needing the extended forward controls. All in all, I would describe the weight distribution of my body and the forward position as more 'active' as opposed to the 'casual' position with the stock tall risers. I love it!
I read up a bit on shocks too. I'm starting simple. I tightened up the tension on the rear shocks by one notch, to position #4 - huge improvement, and probably enough for my purposes (I weigh about 75kg). The suspension is stiffer but much more predictable.
I'm going to try a fork brace on the front and see how that goes, before I start on the task of upgrading the front suspension. That might be enough for my riding style. I like to push the bike a little bit but by no means do I go near it's limits (or mine). Given the improvement in the rear shocks, a brace on the front may be enough to tighten things up a bit.
Was a really fun ride