AC Power box for Hypercube with SSR

I'm building my own version of Tech2C's Hypercube with various changes. For example, I am using silicon heater that is using 220V AC power. Also, my bottom horizontal rails are a bit higher than in original design.
So, in order to get silicon heater working, I'm using SSR. And of course I wanted to isolate high voltage connections as much as possible and came up with this solution that combines cover for power button, power chord connector, a fuse and high voltage part of SSR.

Autodesk Fusion 360 link to the project: http://a360.co/2uOMp1S

The screws and nuts are:
2x M3x35 screws
7x M5x10 screws
2x M3 nuts
7x T-slot nuts for 2020 extrusion profile (look for original hypercube page)
I also used 2 washers for M3 screws just in case.