Thank you guys
Some updates !
My styrene R2 is now R/C and move perfectly around the house.
With the 300mm aluminium base ring :
I cut all the pie panels (yeah I know even the holo one

) and the top of the inner dome :
Glued the outer and top inner together using silicon, I no longer have gaps between the outer and inner :
Cutouts on the inner dome :
I used the idea from other members here (thank you !) to remove the gap at the bottom. Mu spacer brackets are not really nice but they work :
The other side:
With the outer dome :
Some pics of the dome fitted on the body :
Then I changed my mind and decided to build a second droid, all aluminium !
So I repainted my styrene dome :
But I changed my mind once again and the styrene droid will be gray,white and black, R2-Q2 as seen in the Tantive corridors of ANH opening !
I sanded the spine lines of my aluminium dome :
My aluminium R2 has begun ! It will be R2-D2 of course
I have an old Com-B frame, I needed to cut the base plate to get the center leg going into the body to get the correct angle.
Result :
The legs, ankles, feet are custom alu parts made available by a french builder.

I will modify the center foot because the hatch is not flush with the foot shell and not tall enough.

Family pic
I wanted to put my alu ankle cylinders unfortunatly I do not have US hardware, anyone knows which screws I need ?
I reworked my styrene dome.
No more rounded edge at the top of the dome base ring. It's now sharp !
I drilled and put the horseshoe shims on :
Under should details in place :
Today I built the center vents and internals from BobC, awesome parts !
I sanded, filed and roughly polised all the parts.
The inserts of the bottom vent need some serious filing.
Done :
Upper vent, easier and faster to build :
Done :
In place :
Thanks for looking !