Can anyone clarify the 'max uses' value in trial extensions. Is it the number of users that can use the trial key or is it the number of times each user can use the trial key?
It's a rough estimate of the number of users that can use the trial extension. We can't limit the exact number of users to use a trial extension because trial extensions are not product keys. Product keys can be limited an exact number of times. Trial extensions cannot.
Is this the correct approach?
No, just use an "offline trial extension". That you can embed in your app and it won't have to talk to our servers at all.