thoughts… I tend to think of overtone as a close cousin to reverb. Braz rosewood is the king of natural reverb in my experience.
Honduran (genuine) mahog is one of the softest hardwoods while various rosewoods are some of the hardest. The softer hardwoods produce less overtone <-> vice versa with rosewood. Builders pick tonewoods/soundboards with bracings etc based on their specific plan for the model.. so many choices.
I really like honduran mahog for rhythmic arpeggio, good note separation off chord shapes/patterns. Most spruce soundboards work great for me. EIR is fine for this, just has a darker tone and less note separation, also great for background rhythm or singing over. bert 2c
hardness chart:
http://tinytimbers.com/janka.htm