Greetings,

I am operating at an area with an elevation of roughly 1800m above sea level. Based on some reading I've done, I have seen that the maximum attainable vacuum at this altitude is roughly between 24-25 in. Hg. I am getting a steady 24.9 in. Hg on my vacuum gauge and a drop test 30 minutes later shows no losses.
Should I then be satisfied that I have achieved maximum vacuum or is something not right somewhere?

Yes.  Sounds like you have a solid pump that can pull the entire atmosphere for your altitude.

Jason