I don't know about the US, but in Canada Diamox requires a prescription, so you would have to talk to a doctor. Your doctor may not be familiar with this use of the medication (it's a medication used for glaucoma). When I first asked my doctor, in the 90's, he sent me to a respiratory specialist for a prescription, and I had to show up with research in hand. Today, of course, your doctor can go on line if he or she is not familiar with something.
It is true that the literature states starting Diamox 2 days prior to sudden increase in altitude, and use for the first 2 days at altitude. So certainly follow the advice of your doctor, or what you feel is best for you, and not feel that you need to follow the advice of non medical professionals. However the OP asked for experiences with Diamox.
