I just purchased a van with racks already installed, my only advice is don’t over do-it. I thought they were great until I began loading my equipment. I ended up taking alot back out.
In my opinion you only need shelves on one side taking up 3/4 of the wall.
Mine are a chrome wire type which enables you to adjust shelf height. Also a 5ft length of PVC pipe mounted high on the other wall at an angle holds your rake and long handled items well.
Hope some of this helps ya out.
Michael