About using the 100% sizing or the 90% size;
This is the size they were in the original guitars that were built many years ago.
At that time the fret boards were wider than the sizes used today on modern guitars.
If you are building a modern guitar with a fretboard width of about 1.75" at the nut and about 1.13" at the 14th fret then you should chooses the Modern version at 90% of the original size..
This Traditional Guitar Inlay set that can also be used for other Fretted Stringed Instrument with a similar sized fret board.
The drawings for this set were given to me years ago by Chuck Erikson, The Duke Of Pearl.
For years I've searched for but not found any complete photos of this inly set on an original guitar.
If anyone should see this and have a good photo we'd love to see it.