Congratulations on your new accordion, Dave. I play, and I have never used a diminished chord either.

Mine is a Hohner student model, which is all the weight I want to have on my shoulders. The best advice I got about it came from a teacher who told me not to use the box it came in. She was right; putting it in the box jars it every time, and taking it in and out was enough of a chore to keep me from practicing. Now I set in on a little-used dining room chair and I play it much more.

What's a coupler?