This is going to be a frustratingly slow process so there’s no point in trying to ask all the questions right now.
The only urgent questions relate to potentially serious side effects, especially if you noticed anything strange happening to your skin, lips and so forth. If the blood test comes back with strange values, that would of course also raise urgent questions.
Like I said, changing one’s dose is in the guidelines so it’s certainly not unheard of! In your case, the motivation for doing something a bit more complicated than usual would be the amount of time you allowed your gout to fester without treatment.
Most doctors are terrible at treating gout so imitating common practices isn’t a very good idea.
Initially, the effect of allopurinol often seems to increase over time but that’s probably not due to an increased effectiveness of the drug but to negative feedbacks. There are many confounding factors so you may not observe this increase.
There are also diminishing returns (or in other words a diminishing marginal effectiveness) with increasing doses but that’s a different issue.
Over longer periods, changes in your body’s ability to eliminate both uric acid and allopurinol metabolites will affect your SUA even if your lifestyle and diet didn’t change. It would be very difficult to tell whether there is a small change in the effectiveness of drug itself. I’m not aware of any conclusive results and the default assumption should I think be that the effictiveness doesn’t change over time.