I put this jig together this afternoon and can now rip well beyond 24" in width.
I shaped the bottom of the 3/4" thick slats so that the protrusion fit snugly in the upper slot of the front and rear rails. A shorter piece was screwed and glued to the end of those to raise the jig's fence so it will clear the auxiliary table.
The "fence" was installed with the slats installed on the rails, I used the saw's rip fence to align the jig's fence by measuring from the saw's rip fence to the jig's fence both at the front and rear of the saw. This assured that the jig's fence is parallel to the blade. I then clamped the fence to the slats, pre-drilled for the screws, removed the fence, applied glue and then screwed the fence back in place. I also made it extra long to keep larger material more easily aligned to the fence.
To set the width if the rip you have to measure of course from the blade to the jig's fence.
Here are a couple of pictures of the jig installed on the saw


Here is a bottom view of the jig, note how the bottom of the slats are shaped to fit the top of the rails.

Simple... and it works, I already tried it.
Tim
I too am a person who uses the rip scale and also slide those rails as needed. Personally, I haven't run into any problems resetting the rails.
One of my concerns though with ripping very large pieces with the rails extended, is the weight of the stock and how much these aluminum rails can withstand without bending. I seem to recall someone posting several years ago that you shouldn't use the rails as "handles" when moving the BT, as they could bend. While I don't question that, it also made me wonder if the possibility might be there for something like sheet goods.
(Actually I find sheet goods too heavy to deal with on relatively light BT, so I prefer to use a factory edge and my hand-held circular saw to cut them down to size before hand.)
Thanks,
CWS
I was going to ask how you locked it in place but I saw the C clamp in the first pic. Is it rigid enought not to need a clamp on the rear rail?
You know Pappy I honestly don't remember, it's a long time ago and almost three years ago I went to the darkside and bought a ssshhhh sawstop pcs. My memory ain't what it used to be, but I believe the fit was snug enough that I did not need a clamp on the back rail.
Regards.
Tim