Can you explain a little better what you're trying to do?
Are you trying to mount the MFT/3 leg hinges on an MW1000 extension to make a free-standing MW1000?
I'd almost think you'd be better off adding lifts to a MFT-Kapex if you just wanted a smaller table with four folding legs.
Alternately, cut an MFT rail profile in a 2x4, install the 2x4 in a 2x4-DIY sawhorse hinge set, and install the extension table on that.
Others have cut an MFT rail profile in a block of wood and attached it to a wall or stationary bench to accomplish something similar, but I can't find the thread(s) right now.