Just to update the previous posts regarding adding suction control to end of the 27mm Festool hose...it works with a Fein adjustable suction tool coupler (31345078010, approx $35) and a Fein 1-1/16" hose repair kit (31345069010, also approx $35). The total cost of this solution is a ludicrous $70 and 2 minutes, but it does allow the addition of suction control to the OEM 27mm hose, so this all can still fit (barely) in the CT-SYS hose garage. The Fein coupler is a bit bigger than the Festool, so it makes squeezing into the hose garage a little tighter, but still doable. Fits all the tools just fein (haha hoho hehe).
First pic is of the pertinent two pieces of the hose repair kit threaded onto the Festool hose (after removal of the Festool end).
Second pic size comparison.
EDIT update: So as I was putting strain on the new hose end trying to jam it into the hose garage, I was able to pop off the repair kit part from the hose. It seems to thread fine onto the hose, but if you bend and tug at it it can come off. Doesn't seem like a huge problem with normal use but trying to shove it into the hose garage did loosen it, especially bending it at the end. I will experiment with the kit further to see if there's something I'm missing. Alternatively, some epoxy would make it more permanent.