I second-guessed myself, and now I've got Medieval Sleeve Nr. 5

It's simpler. It might eat up more fabric, which is not even sure. But it's simple. Therefore, I'm going to use it on the final silk version. I'm still not sure what I'm using on the blue workdress, where I'm limited by fabric width (100 cm).

This is the pattern layout, the way it's going to be cut out of a 24 x 40 cm rectangle of fabric.



In reality, the two smaller pieces will be on the other side of the big one. The weird polygon goes to the bottom, situated the same way it is on the layout. The triangular gusset goes into the space between the other two, flipped upside down.

The main purpose of Nr. 5 - outside of being simpler - is this:

I thought, hey, this thing is almost grande-aissetted, what if I use this as a base for my Regency dress as well, and save myself some of the mocking-up trouble for that dress?
So I united all the three pieces of Nr. 3b-Something, and got Nr. 4, which was very, very fine, but not entirely.
So I played around it a bit more, used the back gusset again, and thus arrived to Nr. 5. Where I end. Now for real. If I go on, it will be to Regency Sleeve Nr. 1.