My extension stand has only travelled a couple of times. It would hold up fine, but it takes up space as an "L" shaped object. It would be simpler to cut a strip of plywood x inches wide by whatever length you want and concentrate on how to attach that to the mft/3 using something similar to what I did. Then you could use a telescoping outfeed stand or roller to support the outboard end. That saves space and adds versatility in my mind.
Just my way of dealing with this inexpensively.
By the way, if I am correct you can buy the left extension for the older Kapex stand and that will mate up with the slots on the MFT/3 protractor head and will telescope for a longer flag stop fence. I just had scraps.
Peter