I’m trying to catch up on this thread and someone may have mentioned this. When those rings under the tins are annoying, I take them off. Pull one end out and then the other. Sorry if this is a redundant statement.
I did a swatch on 90 lb arches to fit in that tin. I know that seems kind of thin, but it works well for swatches and I’ve been happy with it. I have full sheets of it. I think I could only find it in full sheets. I’m happy to mail you some if you want to try it.