See, I could never understand the carrying 2 to 4 of the same molds at diff stages of wear, but to each his own. With all the diff molds out there, I like to carry a diff disc to do a speciffic job..ie..hyzer, straight, or anhyzer, but some think that's nuts! It would bum the crap out of me if I spent months breaking in a disc to do a job and loose it. Or what if you loose the semi broken in one? etc...I could see this as a must when there were few choices in molds, but not in todays market. Heck even the "same disc, same feel, same throw" doesn't make sense to me, because you can still do that with a diff molds.
If you are worried about loosing a disc and having to start over, I can see that concern. What I like to do is use the new discs for part of my warm up. Then they get some break in time and when I loose a disc I can just plug the new one in.
I feel for you as a fellow glass back, but another option is a backpack style bag. As much as I hated the Revo Dualpack design. It put a lot less pressure on the lumbar region of my back, plus it kept the weight close to my body and reduced rotational pain as well.