Can't argue with "pros" but I can share our personal experience which spans over 20 yrs and has always worked for us.
First, see if you can find a contractor/installer that will dig out extra depth and use an expanded depth liner. IMO - one of the worst things about AGPs is inadequate swimming depth. Our installer dug a gently sloping floor for our 27ft round AGP to a center depth of just over 6 1/2 feet. Our walls are 52 inch and since water depth is usually about 4 inches below that our edge depth is about 4 feet to about 18 inches out at which point the slope begins.
The second biggest weakness of most AGPs is the filtration and pump system. Find an installer that will install a second return to the pool from the filter - I would also HIGHLY recommend having a center drain installed. Trying to depend on a single return (the skimmer) is terrible.
We would not buy a AGP "package". We recommend you show for a pool and liner separately. We recommend you buy a more powerful pump than usually comes with a AGP and then have a contractor that will hook it all up and add second drain and second outlet.
We paid a little extra and the end result was the depth and filtration power of an in-ground pool type system over which we put up the AGPool for a small fraction of the cost of a traditional concrete in-ground pool. You can not believe how much better and easier pool management is for an AGP with a decent and power filtration system.
Now Back to Topic - yes, he also installed a Hayward in-line chlorinator - We are not arguing with others here - our personal experience is we have used tri-chlor 3 inch tabs for all 20 plus years with never a problem and we have never felt the need to test for CYA - if our free chlorine is blocked we just adequately shock with liquid chlorine which solves the problem and frees up our chlorine. We highly recommend use of an in-line chlorinator and tabs with stabilizer 'built in".
Guess there are cases to be made for keeping it simple or making it more complicated and at the end I believe there are no "right" answers to the best way to maintain your pool water - what works for you and results in crystal clear and clean pool water is the "right" answer for you - and that answer for us has been in-line chlorinator, Hayward C-900 in-line filter.
Good Luck developing the "right" answers that work best for you.