Here, I could not get [#6-32 X.75 (M3.5 X 20)] bolt & nuts…
Can I use [M3 X 20] or [M4 X 20] bolts & nuts instead?
Ebay or something similar? I am not sure how well the others will do. I would guess if you have to go with M3’s. M4 will need to get drilled out.
I used M4, just drilled the holes a bit, works fine.
M3.5 is not common, so would be cool to have the models with M4 instead 
Thank you! I will try M4.
I used M3, so no problems for you 
Had the same problem here, and as someone said drilling worked fine, cause you only enlarge the holes like 0,35mm. Isn´t a big issue for the holes on the edge of some parts.