https://www.amazon.com/Keychains-Rectangular-Unfinished-Engraving-Personalized/dp/B0CWRPQ4KH/ for the keychains that fit within (do note, this is created in the metric system, so 6.5 cm x 2.8cm)

holes in the corner for alignment/fixing the rig to your honeycomb /workspace

Let me know if other sizes are needed, so I can fix where needed. 
if requested, i will drop my F3d file as well