you keep mentioning your engine builder here, and i'm failing to grasp what it is that you mean by that or what he actually does, or did in this whole process?
if you employed him to build your engine, then ALL of that cam stuff should come under his purview.
anyway, cam is sus. i would pull it down and verify with a degree wheel, or at least check the lift numbers at the rocker.
one would, indeed have to consider the time it would take to verify the camshaft; and in response one would also have to live with the unknown and poor performance if not verified.
this leads to the conclusion: there is no easy button.