This is a lovely accordion you have! I've never seen a stepped LH freebass outside Scandinavia and none of the top players I've heard have used it either. Seems strange because it looks like it's a better design. Perhaps there is some disadvantages?I have used some markers on both sides of the bass-strap as seen on this image. Now I used my own 3D-printed parts. This is a good Idea and heard it from Øivind Farmen