As unlikely and disturbing as this might sound, one must prepare for the worst. The worst in this case turns out to be pretty convenient for those of us that keep programmable calculators close at hand including in the toolbox.
My calculators of choice have always been Hewlett  Packard and I have come to really appreciate the virtues of RPN as my personal faculties fade.
Writing a little program to save in the calculator was much less of a chore than making the calculation of the AMP v2 geometry  and that wasn't too tough. Given that the AMP v2 business is accomplished by the caliper measuring the change in length of the base of an isoceles triangle and that the difference is 152.40 mm for a change of 90 degrees, following provides the unique solution of leg lengths that make this work.
Where:
A = the change in base length
a = the angle opposite A
OA = the desired obtuse angle
C = the length of one of the equal legs
The solution for the leg lengths at an obtuse angle = 90 degrees is had by
A = 2C x sine (a/2)
At an obtuse angle setting of 90 degrees, a = 45 degrees. Therefore at an obtuse angle of 180 degrees, a = 135 degrees. Given these two known conditions, the lengths of A and C can be calculated as follows.
2C x sine (45/2) + 152.40 = 2C x sine (135/2)
C = 140.799 mm
A at obtuse angle of 90 degrees = 2 x 140.799 x sine (45/2) = 107.763 mm
Solving for A for a given obtuse angle is then
A = 2C x sine ((OA45)/2)  107.763
Solving for the obtuse angle for a given A is
OA = 2 x (arcsine ((A + 107.763)/281.598) + 22.5)
A simple program for the venerable HP 10C is then
fLBLA
45

RCL02
X
RCL01

fLBLB
RCL01
+
RCL02
/
gsin1
22.5
+
2
X
To calculate A, enter the obtuse angle, press enter, and press f LBL A
To calculate the Obtuse angle, enter A, press enter, and press f LBL B
After all this, the good news was that the result corresponded to the APP!
Bill