I started with a surplus, solid-core door, though the thicker, the better. Using straight edge and router, cut channels for the tracks. Have had it up and running for about 20 years. No deformation, no changes to the tracks after a lot of use. The T-Track bolts distribute the clamping force across a lot of area; and there are four bolts per press in my design.
The set-up allows me to easily unmount a press without changing any settings. I can slide presses to one end, or the other of the table and have plenty of room to work on a particular process or project. The tracks allow complete flexibility for how the available space can be used -- there is still a useful table available when necessary.
I used, and recommend, the 1 3/4" T-Track, 1/4" steel plates permanently attached to the presses, the T-Track bolts (absolutely), and knob-nuts for tightening. Very solid, durable, and flexible set-up.
I put a space in the track at the center of the table so presses can be removed or installed at that location, also handy for clearing the track if something (primers) falls into it during the process.