If the doctor evaluated you while you were on mestinon...
 

If the doctor did all his in-person tests (push-pull-hold, etc) within 1-2 hours after you took a mestinon dose, is he going to detect much?

Office staff told me to take the dose as usual before coming in.
Now find that, by way of checking on the referral to a neuro-ophthalmologist, that he says he didn't find indications of mg during his exam.

Only bloodwork I have is AChR test, which is negative. Further testing is blocked by insurance hell that may never get resolved.

Every description of MG I have read describes what I have been going through, for years, to a T. Exactly. Full body, not just eyes. My regular ophthalmologist is sure I have MG (he's the one that first put a name to it, and when I read about it, it was a EUREKA! moment). Mestinon works wonders. People who barely know me and rarely see me, can see the difference.

So, if he did his exam while I was a the peak of a mestinon dose, is he likely to have detected MG, or would he be more likely to see me as "normal"?

That all depends on how badly a MG patient is doing. A mild to moderate case of MG may be masked by Mestinon (clinically). That shouldn't mask antibodies.