Phone Wall Mount Ball Joint

I made one of these: https://www.thingiverse.com/thing:2448971 and realized it could use a 90 degree turn on the end. So here it is. Holes are designed for M3 sockethead screws and M3 nuts.

I get confused over name of the screws Some call them caphead and others call them sockethead. This type is what I am talking about https://www.mcmaster.com/standard-socket-head-screws