For the lamp head design, i wanted to have a smooth transition between the body and the tip..
I tried to use the "interpolation" functionality of inkscape but it is difficult for the plugin to guess what kind of morphing you want between shapes and it can be done only between shapes with the same number of points..
So i decided to do the morphing manually, by stacking the shape one over another with transparency and different colors:
I'm pretty happy with this methodology: i use the center hole that will allow me to glue these parts on a carbon tube as a reference point. Then i can control and correct the morphing between shapes to smoothly evolve them into one another.
I did two drafts to see how i could morph into a flatter shape to host the LEDs

Once i was kind of happy with the result , i imported it in blender, offsett each shape by 3cm and solidified them with my 3.6mm plywood  thickness.

I also started a foot design but i'm not sure how to link them elegantly to the base of the tentacle...
In the render below , i also adjusted the number of vertebraes to match the one i already have... As a result, the lamp has shrinked a little bit...
Following the dry assembly, i also figured out that the base of the spine should be tilted by 15° or more: it will move the cg a bit backward and avoid a too big or too heady foot, and the aesthetics and kinematics will be better in my opinion

I also contacted Brian from https://www.poormansguidetoanimatronics.com/ and he kindly reassured me on the soundness of the design and suggested that i should keep an eye on the twisting of the discs around the center shaft. I replaced the lateral cables by piano wires and thin carbon rods and it definitely helped to forbid lateral movement but i still wonder how i will fix the disc on the shaft.
I'm also weighting the option of removing the rubber spacer between the disc to have a lighter tentacle....