I agree with Kev, design the cabinet to suit your comfort and work style.
After years of keeping my systainers stacked under my MFT, my back was screaming out that I should make a cabinet to allow easier access to my Festool tools.
The cabinet I built provides the necessary storage/access for my Festool systainers and supports my MFT at a more comfortable working height (for me). The MFT work surface is now 39" off the floor, comfortable for cutting and assembly work. I settled on two storage columns made from 3/4" plywood. Each storage column is two systainers deep, and measures 19 5/8"wide x 29 1/2"high x 30"deep, out face. By locating the cabinet sides flush with the face of the MFT there is room for 6" wide drawers between them. Each column is fitted with four casters (2 1/2"h) and could be a stand alone unit, should I desire to separate the unit in the future. The unit is mobile which allows me to access all sides of the work surface and allows me to roll it back into its storage location.
The MFT is held in place by wood blocks positioned behind the MFT corner castings.
The present arrangement provides space for 14 systainers; 2-Sys 4's and 4-Sys 2's within the left column and 2-Sys 3's, 4-Sys 2's and 2-Sys 1's within the right column.