I recommend viewing the newer video at    • Fusion360: New and Improved Finger-jo...   after viewing this one.

A newer version of this model is now available at
https://www.thingiverse.com/thing:283...

In this video I design an open-top box with finger-joints for cutting on my Glowforge laser. All of the fingers in this model are consistent in width, and the number of fingers automatically adjust based on the dimensions of my model.