I am good, pretty busy with the work at Prakti and other stuff, there is a lot of good projects and ideas coming up at Prakti, we are living enthusiastic times!
I saw the GIZ 'Pulumde' when I was in Benin, interesting design, looking sturdy like a Roumde and with a grate like a Pulumusa. I remember secondary air was exiting above the charcoal pile from a metal tube attached to the grate, but it wasn't working well, and I think it was taken out later on.
The improved malgache I made wasn't really convincing in terms of performances. Something wrong with the air flow, I guess. Needed a lot of design work, way more than I could do with my small knowledge. Perhaps a two-stage door like you are proposing would improve the performances, yes.
I think GIZ with the Pulumde and you with the improved malgache are on to something.
A few pictures of the improved malgache are attached.
Now my main concern was to make a heat-resistant combustion chamber/cone/grate? Either good and thick metal, either a ceramic one like the POCA you showed me.
Cheers,
Xavier Brandao
Casual Παπουτσια