Thank you for posting this. Its more helpful frankly than all the other things I've read or seen on this very interesting bike.
I know the following would help me characterize a bike I have not seen in person, much less touched, and will help a bunch of people like me that have the same reference point. You are familiar with the ugly-but-lovable Weestrom.
Comparing the two, I can see from some of your remarks the obvious differences: the Weestrom is a roadbike that just happens to be able to do things a roadbike shouldn't quite so well. But would you Contrast the two on a few specific riding points, so we who know the one can understand the other better? For instance:
1. Contrast the two in terms of loaded handling on Gravel: how would the two, with similar tires, compare on that surface?
2. Any comments on the performance of the ABS system on the two?
3. Similar to 1 - on other surfaces such as hardpack or loose rocky
4. Weight distribution. They are both similar in weight, but looking at how they are made, the GS should FEEL a lot more nimble in the front. I'm betting weight distribution front-tire/rear-tire is remarkably different. It would seem that center of gravity on the GS is lower and shifted a tad to the rear.
5. My personal issue....[don't ask]... How would you compare the two going down a STEEP downhill grade on a loose dirty/rocky surface?
It looks like the 800GS has an advantage in engine performance, and the Weestrom has an advantage in Range. Is this right?