Hi Kees, so sorry you are having so many frustrations. It’s been a year now that you’ve been working on getting a rocket stove hasn’t it?
There’s so much that goes into a wood stove, and so much more for a rocket stove.
I wonder if you want to look into buying plans for a riser-less rocket stove from Matt Walker. He has several designs.
https://walkerstoves.com/shop/
When I finally get the support built, I plan to use one of Matt’s plans inside my house. I don’t think I could live with the frustration you have endured. Matt’s planns tell you brick by brick exactly how to build, and I think he has a good track record and possibly a good guarantee.
The rocket stove is complex, and you started with complex modifications.
As hard as you have worked, I really hope you finally get a nice rockety rocket! And SOON. Good luck!