OK, this is what I've decided for my work-in-progress CBG...
It's gonna be fretless, but marked. Diatonic w/blue notes, 25-inch scale, tuned open G.
What I want to do is use zip ties in the fret slots, sanded flush, but the blue notes will be blue zipties. The others will probably be white.
Can't find a fret calculator with a blue note option. Anyone know of one? I do like the StewMac, but then there's the blue note issue...
Look up an image for the G pentatonic scale, it will show the blue note ( C# ) locations, this is independent of scale length. You'll note that the blue note does not fall in line for any combination of G tunings. Because of this you would have to cut the zip ties into sections at the blue note locations. You might want to try a different marking method such as a blue dot inlaid on the fret board at the C# frets.