A question about intonating a dulcimer
Instruments- discuss specific features, luthiers, instrument problems & questions
I went back to look at the photos of the spacer and fret. Someone obviously messed it up.
Frankly, if I was dealing with this, I would remove the plastic spacer and throw it away. I would make a new spacer from hardwood or plastic. I would probably then cut a new groove to fit the width and height of the spacer closer to the zero fret. Alternately I would re-cut the spacer hole to square it up, glue in a filler block, and then cut a new slot there to fit my new spacer.
I would also reset the position of the middle string to the middle of the fretboard.
Sorry about misleading you about sloping the grooves. That applies to a nut, not a spacer.