I have the Shinex. I keep it in a Maxi-Systainer along with Festool foam pads and other pads. Not sure why the Plug-It Gods did not favor the Shinex for that type of cord.
My Maxi-sys however, is an older one that's not as tall as the current one, so there's little wasted space. Somewhere on talkFestool there's a review of my Shinex and a pic showing the two different maxi-sys's side by side I think.
If not, now that I own current Maxi-Systainers which house the Planex and its gear, I can always take a new pic to show you.
I have Sys 5s that I could pop the Shinex into for a fit check, but I really like having the tool mounted horizontal in the Systainer with accessories like other Festool products.
I used the foam insert in my Maxi-Sys to keep things from bouncing around.