how to stick 2 boards together (panel + board)

[VEGETA]

Hello,

I have a small board 100x90mm with its top panel as seen in attachments, not final placement but dimensions will be similar.

I want to use Matte Black PCB since it looks good and cheap.

I have couple of options to do it:

Option 1:

make the board using regular black to be cheap then make 2 matte black pcbs; one for top panel and one for bottom panel.

to stick them together, I use the following:

stand-offs:
Wurth 970300361 M3 30mm -> between top panel and board.
Wurth 970050354 M3 5mm   -> between board and bottom panel.

would need 4 of each for each unit.
screw:
Keystone 29316 M3 L=16mm -> need 8 per unit.

Option 2:

use same Wurth 970300361 M3 30mm stand-off (female-female) and 2 screws per standoff without making a bottom panel, here pcb itself will be matte black and will ditch the bottom panel.

will be low clearance in bottom since just screw head is there.


Option 3:

use a non-threaded stand-off like: https://www.digikey.com/en/products/detail/essentra-components/005298059905/4104020

with rivet like these (with suitable hole diameter):

https://www.digikey.com/en/products/detail/essentra-components/167205069902/7794369
https://www.digikey.com/en/products/detail/essentra-components/QTPF-1BK/3814563

same as option 2, with the pcb board itself + top panel, no bottom panel.


Option 4:

similar to 2 and 3 but instead of rivets and screws... something like rubber feet so that it looks more neat especially on bottom to have better sitting (not so important).



Option 1 is more complicated and expensive, so what do you think?