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When modeling a compound fretboard, there are two methods of doing so, and we don’t know which is correct.
Primary method – Create two arc lines, 12” and 16” radius, and place each at their respective fretboard ends, one at the top and the other at the bottom. That’s easy, but here’s the issue. How should those two lines be aligned to each other when viewing the arcs from the headstock? Should the top centers of the arcs be aligned, or should their edges be aligned? That’s the question.

If the tops are aligned, so that the fretboard will have the same thickness along its entire run, the edges will be of different thickness due to the fretboard’s compound radius.

If the arcs sides are aligned, so that the fretboard’s left and right edges will be of equal thickness, the fretboard’s center at the heal will be higher than that of the Nut, due to the heal radius being flatter.

So, which is correct?

Should a compound radius fretboard be of equal thickness, from top to bottom?
-Or-
Should it be thinner at the Net end, and thicker at the heal end?

Both are possible, depending on how you align the arcs during modeling.

Assuming you have enough adjustment at the bridge to cover both configurations it doesn't matter at all which you choose. With the arc apexes aligned the edge thickness difference at each end won't be much more than .02" and no one will visually see it.

The thing I'd worry about is being sure the radii used are appropriate to the taper you are using. If you haven't calculated the precise radii necessary then the result you achieve won't be as accurate as it could be. Since you're using CAD you might as well calculate and draw it perfectly. Maybe you did this but since you mentioned 12" and 14" (rounded off numbers) as the radii...well that sounds like you may be sort of guessing.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Since the fingerboard is usually a higher quality tonewood than the neck (because it has more effect on the tone than the neck) you want to remove the least wood possible from the specific fingerboard blank you are working with.
Think of all those great old acoustics with brazillion rosewood fingerboards and bridges.