That's almost what I ended up doing, except rather than putting the flat piece between two rows of studs, I put it on top of the studs and had adjacent stacks to stabilize it.

Two flat pieces back to back are very very close to the width between the sides of two rows of bricks separated by one row of empty studs.

Here is a photo [1]. Here it is with the three top braces and the cable holder removed so you can see everything [2].

This the LEGO compatible case I'm using for the camera [3].

[1] https://imgur.com/a/ggNe5uM

[2] https://imgur.com/a/jz525N7

[3] https://www.amazon.com/gp/product/B01F19WI0O/

If you want more options get some of the Technic sets - the pins and arms provide lots of freedom.

it also stretches the studs apart a tad to much, so it's not recommended.