Hey Martin,
Nice! Looks like you are getting great results! Can't wait to see more And thanks for sharing the pics of your collection!
Do you only have the diamond plates right now - 100 to 1000? If that is the case, and you are intending to buy just one more set of handles for now, I'd go with a set of strops before I'd get the ceramics. I know that there are people who will disagree, but I think that the strops put on a nicer final edge, and they shine better. 5 and 3.5 micron is next logical step after 1000. As for substrate - I use leather for my initial sharpening but the balsa has the advantage on touch ups of being able to stand up edges that the leather won't and the shine/edge is comparable between the two so I think it is really a preference call.
If you have strops already - then I'd add the ceramics prior to going finer on the strops as IMO they really take out the scratches from the diamonds nicely. I use them primarily when I'm going for superior mirror finishes after the diamonds and before I strop.
I found most kukris are easiest to do in two steps since depending on how big the belly on the blade is it can be hard to get the stones to track evenly along the full length. So, position the knife with the handle closer to the vise and do the rear of the blade into the back of the belly first - using a sharpie to see how the stones are tracking and stopping where the line cleaned off by the plates stops cleaning the full bevel and comes down onto the shoulder. Sharpen that section to just behind that point where the stones stopped tracking working through all your stones to whatever grit you intend to finish with. Then, when you are done with that section, move the blade back in the clamp grabbing close to the tip and work the belly to the tip overlapping the section you already sharpened about an inch or so. Again use the sharpie to find the position where you can clamp the blade so that you match the angle of the section you already did and carry it all the way to the tip without widening the bevel - and work through all your stones again making sure to work the overlap. If you have strops, you can hit the full blade length when you are done to blend it all together. I'm gonna try to attach a video of a cold steel kukri that I did at a show - about 31 degrees each side (measured with angle cube since the blade thickness throws off the angles as shown on the base rod) sharpened with the Pro-Pack Stones - diamonds from 100 to 1000 then leather with 5 and 3.5 micron paste.
PS - might try with an inexpensive one prior to jumping into the beauties in your collection - they sure look nice and I can't wait to see your results!
Have Fun!
Bob

[video]http://youtu.be/0vCZ51lj7BY[/video]