Steps
Step 1
Design in Sketchup. The stud positions are marked.

Step 2
Test the mounting design, using 12mm timber dowels. Tried a prototype in the garage, with a bag of concrete. Only minimal deflection.

Step 3
Cut the shelf panels, drill holes and glue dowels and put finish on the boards.

Step 4
Measure everything and mark with tape and double check. Pre drill holes through the chip rock into the studs. Screw in floating shelf mounts and at the end, slide the shelfs in.

Step 5
Finishing up and triing to fins s[pace for everything. I really enjoyed the process, and it turned out great.