I just finished adding to my site a chord chart system that calculates a chord's difficulty (categorizing by "Easy", "Moderately Easy", "Moderately Difficult", "Difficult", and "Impossible") along with a numerical difficulty rating.

I've also included finger placement on each of the chord charts. I wrote an algorithm to determine the placement because I wanted to be able to work with multiple instruments and tunings.

Here are the charts for Gm7 on Guitar

You can indicate whether you fret with your thumb and whether you like barre chords on the "Tab Options" tab here .

Given that it's simply an algorithm, I'm looking to improve it. Are there any chords you can see that don't have the correct finger placements?

I appreciate your help and I hope this is valuable to some of you out there!