[RichardM]

André,

A little breakout on the back like that looks OK filled with DARK brown or black wood filler.
Just looks like a small knot in the timber.

Lots of my projects end up having some "knots" that weren't there when I started.

Looking good though.
I hope my first effort of guitar routing turns out as well.

(I chickened out of making my own templates, and am waiting for a set of Ron's to travel across the Pacific to me.)

P.S. I little tip if you use the filler. Seal the wood first, stops the filler from going anywhere except the hole.