You're welcome and thank you! Yes, I also tried similar joints on one lamp. It turned out that I am too impatient and imprecise to create such joints by hand. Dowels seem much easier and achieve about the same thing. The angle doesn't matter in this case as there aren't large forces involved, so (1) initial hand adjustment and glue should suffice and (2) the Kumiko frames will push the the connecting bars in the right angle anyways.