I have the Roberts Quilting setup and the actual height of my table is 30" and then has an insert (depth) area for my machine that adjusts to the height of the table with another insert (piece that was made specifically for the machine) that fits around the machine so my machine sewing area is level with the table. Geeze, hope I'm explaining this correctly.
I went to the Roberts Quilting Cabinets website and they don't offer the setup I have anymore. I will try and check further for you to help in understanding what my words lack.
Okay, this is what I have but have added additional pieces. It is the first picture shown:
http://sewingsupplywarehouse.com/mo898ulquta.html