Custom Plastic spacer/adapter/Orienter Bracket

I need a small, purpose-built plastic spacer that locks a metal bracket for a shelf firmly against its supporting metal bracket. The spacer must be custom-fitted to the exact profile of both parts and incorporate grooves or slots that positively engage with the bracket so nothing can slide forward or rattle.

Size of the spacer/adapter/Orienter is no more than about Height 1.5"-2" X Width the same X depth of 1/4"

You will receive photos, dimensions, and a simple sketch of how the shelf sits on the bracket today; your job is to translate that information into a ready-to-manufacture design. I plan to 3D-print the first prototypes, then move to metal once the fit is perfect, so native CAD (STEP or SolidWorks), STL, and a clear drawing with critical dimensions are the expected outputs.

Please model the part so:
• The face touching the Metal beam is wide enough to fit around the update beam but is not too loose that it does not sit loose and allow the shelf to move.
• The grooved side locks neatly over the metal bracket—or into—the metal bracket profile without tools.
• Draft angles, radii, and wall thicknesses follow standard moulding practice.
• Will also require a track that has a 90 degree angle to allow for a shelf to sit at 90 degrees for the sake of displaying books or records.
• Must be able to take a clear picture and transfer that image into software to scan for real life measurement specs

I’ll test the print in-house; if adjustments are required, a quick turnaround on revisions will be appreciated.