Trip did not go as planned, we got there and decided that the trail was too tough for us. So, we car camped in the campgrounds and day tripped on the trails. We saw three other groups trying to tour/bikepack the trail and two of the three groups had run out of water hours before they got to the first campground, the one group that did not had done a six mile detour to stock up on more water. Looking back, we made the right decision.

Now, back to the topic of frame bags, my frame bag worked great. This was the Large size Ibera bag on Ebay for a really cheap price. There are a few out there that were called "large", the one I have has two zippers. As I noted above I hand sewed on a strap to attach to headtube and to down tube, I did not use the strap on it for the seat tube. As you can see it fits in the front part of the triangle very nicely in my frame, I think I got lucky to find a cheap bag that fits so well it almost looks custom.



I almost never noticed it was even on the bike, my knees never rubbed on it or had any other problem. I am guessing that total volume was about 5 liters. I carried my spare tubes, tools, about a liter of water and some other small heavy stuff in it. One day I pulled out the water and instead carried my rain gear in it. You can see in the photos below that it was pretty narrow in the frame, I am guessing about 3.5 inches (~~ 85mm to 90mm) where it bulged out the most. You were concerned about width, I think a good rule of thumb would be any width that is as narrow as a water bottle is unlikely to be a problem and if you can figure out what part of your triangle your knees could contact it, any part of the triangle forward of your knees could allow the bag to be much wider.



To avoid having the straps rub off the paint on the frame, I cut strips of inner tube rubber and wrapped it around the frame, then wrapped velcro around that to hold it in place. (Electrical tape probably would have worked just as well, but on my frame the clear coat over the paint flaked off when I did that before with electrical tape.) Then the bag straps went over that.