I didn't have t-nuts on hand so I remixed the part to clip right into the extrusion without the need of additional bolts. This might not work for someone who wants to mount this in a vertical orientation. 

I printed it using PETG but PLA should be just fine, since the parts don't have to withstand a lot of force nor weight. 

These ware my print settings, but you can choose whatever works for you best :)

0.4nozzle 

15% Infill with adaptive cubic pattern

4 walls, 3 solid Top&Bottom-Layers