Eleksmaker x carriage tension adjuster (remake)

There is this existing design for the EleksMaker A3 Laser https://www.thingiverse.com/thing:2482004
But I own the smaller A4 size and the measures don't fit.
This is basically a complete new version but I borrowed the design idea above.

Additional parts:
- 2x M5x30mm
- 4x washer for M5 screw
- 2x M4x20mm

The screw head type doesn't mater, but the groove in the part was made specific for a inverted hex (imbus) type.
I actually used only one M4 screw an pressed a small 5mm bearing bal