That is my Bossa signature guitar I used for the BEBOP album. Yea, it
looks like a "rock" guitar for sure especially with the yellow stripe but
this guitar won out for the album for one reason - the neck has a natural dip
down near the 12 fret and beyond towards the bridge. With the neck truss rod
set almost straight, the slight dip down allows notes played up high to not
"fret out" with kind of "low action."
The picture has me looking down the neck as to check the bow of the neck.
I set all of my guitars truss rods to nearly straight. Other than the viewing
noted in the picture, the way to check the neck is to hold down (finger) the
high "E" string at the first fret with the left hand and hold down (finger)
the high "E" string at the highest fret with the right hand little finger.
Now use the index finger of the right hand and fret a note while still
keeping the other fingers holding down the notes mentioned.
When using the index finger to fret, if the high "E" string has no room
to travel towards the frets, the neck is too straight or reversed bowed. The
idea is to adjust the truss rod to the point that this test allows a very
slight travel towards the frets.