Battra, when you get that much 127 E-6 made up, you'll just have to spring for E-6 chemistry and do your own -- then never a problem getting your spool back...
I've been making 127 from 120 by a more, um, manual method -- but mine gives 16 exposures in a 4x4 camera, 12 in a 4x6.5, or 24 in a 4x3 (though one must mask the camera frame by a couple mm in the full frame or half frame to avoid overlaps, especially when advancing with a double window half frame).
I use a snap-blade utility knife with the blade fully extended to cut the film while still on the spool. Instead of cutting both edges, I keep the 6x4.5 track intact (though cutting the center would work, maybe even better, in the camera, it's twice as much hand-aching effort). I mark carefully, all the way around the roll, and then roll the 120 roll under the knife blade until I begin to cut into the plastic spool core all the way around. This part is done in subdued light -- the edge fogging produced has been trivial.
Next, into the darkroom: I recut the leader to a centered point and start it on the 127 spool, turn out the lights, and start rolling. When I come to the film start, I untape the film and tuck it into the 127 roll. When I come to the film tail, I tape it to the backing with a previously cut strip of masking tape (it's fairly hard to get the tape straight, so it pays to cut it a bit shorter than 46 mm -- I usually keep it under 1 1/2 inches). Once I wind off to the end of the roll, I temporarily tape down the end and, still in the dark, salvage the 16 mm strip left behind to make reloads for my Minolta 16 format cameras -- this goes into a black 35 mm film can for later use. Once the lights are back on, I recut the film tail to a centered point, fold it under, and tape down the end, then store the 127 roll so produced in a 120 film can until ready to use.
Though it produces considerable hand stress, and I keep thinking I need to adapt a tubing cutter with a rolling knife type blade to simplify the cutting process, it works, takes only about ten minutes per roll, and, with the film backward on the spool, puts the 6x4.5 framing track under the 4x4 window. The frame numbers count down instead of up, but that's no big deal. I haven't noticed significant edge fogging, but again, I store my film in 120 film cans before loading and after unloading, until processing. That other page didn't mention that his cut-down 127 wasn't usable in a 4x4 camera without a frame counter...