• Based on my experience, i think you can safely reuse the model from nigh to night, you just need to solve and recal your pointing position

I do.  Thanks.

• There is a built-in sort of check in APPM where you can skip model building and just assess the results. I am not in front of my computer so I can't tell you the details there

What I found checks each point, so it takes the same time to process as it would to rebuild.  Hence the thinking of a sanity check instead of a complete verification.