Last night I’ve glued the lower longeron step by step. The front-most joint with 30 min epoxy and a heavy duty clamp because of the sharp bend, the rest with Aliphatic and smaller clamps:

This clamping technique is working quite well. I even don’t need to fix the frame to the board, ensuring a stress-free assembly:

And after gluing all joints of this fuse side this is the result:

I’m going to taper the tail block, glue on the ply doubler, and then I can start with the other fuse side!