Nice of you to pop in
And yes, the green wizards forum does not seem too active, but they usually have a couple of people online most of the time, and there’s some 300 “hello-posts” (none of mine though I admit). I think they are interesting from an ethnographic perspective because about half of them seem to be Luddites that are sharpening their quills already for the day the light goes out (locally). They recently started preparing the transition from blog to mail. Many of them are pretty old, and even though they have this “complicated relationship with technology” there are quite a few active bloggers in the crowd. So in short, (online) active is always relative. 
Regarding the biochar and the pictures: I have to say all of them were pretty heart warming! And by your description your oven is a pretty thing as well. I wanted to look a little closer at the ceramic rocket stove as well, I think there was a project on that here. I made some drawings at some point but in my current situation there is no point in going beyond that unfortunately. I do have a little background in pyrolysis and carbon, but not on the low tech side (yet). I’d also be interested in looking a little deeper into pitch based carbon fibers, and if it is at all possible to break that down into at least a semi-cottage industry. Lastly, perhaps you’d have some input for a friend who operates a little mobile mill and is slowly but surely drowning in sawdust (I think) - there must be some way to turn that into char without too much hassle…