In my experience the detached cylinder is used mostly on bottom dump hoppers, and very short cars such as cabooses. On the EBT hoppers the brake cylinders are situated on one end of the car in a very short space, which requires the cylinder to be placed beside the reservoir. And of the one extant Sumpter Valley caboose with it's original brake system the K1D is used.
On all wooden cars it is a tight fit to get all of the brake rigging in without interfering with something else, but not because the combined cylinder is too long. I had to redesign the brake rigging on SV coach #20, which is 42' long, and it was a challenge to fit everything around the queen posts, truss rods, bolsters etc.