for determining the neck angle couldn't you just make a imaginary triangle with the bridge, strings, and guitar body: the height of the bridge (all the way down, middle, all the way up, your choice) is one side of the triangle, the length of the strings is the hypotenuse, and an imaginary line perpendicular to the bridge that goes to the end of the strings is the third side
now you have a right triangle. you can use a trig function to find the angle, you dont even need the "imaginary" line
x = neck angle
cosine x = bridge height / string length
i think this would work