I have and use the cotton carrier system on occasion.
I did use it hiking at Yellowstone National Park. Had a Nikon D500 with the 300 AF-P PF lens + TC1.4
Hiked around there for a week, probably 8-10 hours a day. Was like I was carrying nothing.
Mounted that in center position it did just fine. Allowed me to have full range of motion and quick access to the camera when needed. Didn’t interfere with the camera backpack either.
I do use it occasionally for when ever I need to be very active. There are times when I need to crawl around or move quickly and this setup is good for that.
I’ll have the Nikon Z8 with the 70-180/2.8 in center position, then have the Zf with 28-75/2.8 on the right side for a 2 camera setup.
I recommend using the tethers until you get used to putting the camera onto the harness. It takes some practice to seat and release them quickly.
** updated to correct a bunch of auto correct mistakes.