The board will only announce youth and training facilities upgrades after the end of the season. Construction will start right away and will finish in the fall. So if you asked for an upgrade in September, they won't make the official announcement until May or so (although you should know right away if they accept the request) and it won't actually be finished until at least a year after you first asked. The best time to ask is immediately after your last game of the season, since this is when your facilities may have degraded and if you did well in the league or picked up some trophies then the board will be more open to requests. You'll only have to wait a few months for construction to finish.
I usually don't buy unless PA is 3 stars or better. Sometimes I buy 2.5 star potential players. Get scout reports on prospects and pay attention because sometimes they will say someone with 3 star potential can be a "good Premiership/La Liga/etc player" and sometimes it will be "leading player." Sometimes they will also note that a player would be a quality signing and at others only a good signing.
I think that scouts are pretty accurate at judging current ability and potential ability, but when you are looking at 15 and 16 year olds, a regen with 150 PA and 180 PA might both be rated 3 stars. You just need to monitor them, get them some tutoring and decent training schedules with a bit of first team/loan action and assess their progress. If by 18-19 they haven't gotten to the point where they look like they could eventually get into your first eleven then start shopping them around and listening to offers.
I read somewhere, and I'm not 100% sure if this is true but it does make a lot of sense, that your scouts' assessment of current ability and potential ability is only based off of CA/PA points. What does this mean? Imagine you have two GK. One is 3.5* CA, either-footed, very strong with both left and right, with great physical stats but mediocre mental and goalkeeping stats. The other is 3* CA, right-foot only with middling physical stats but good mental and GK stats. Foot strength and physicals take up a lot of CA points and are not very useful to GKs (with the exception of agility and jumping). Since the scout report is just based on CA points and not actually how well they will play, the 3* GK will outperform the 3.5* in this scenario every time.
This needs to be taken into account when looking at players to sign. The first thing you should do, even before going to the full scout report, is check their attribute graph. Once you figure out what the graphs should end up looking like for world-class players it is easy to see at one glance whether a regen is going to be worth your time or not. If you see a regen with a good graph for a youngster and the scout report says he is at a low level of CA, e.g. less than 1 gold star, with at least 2.5* PA, then that means he has a lot of room to keep improving on his already good attributes and could be a future star. But if there's a regen with a poor graph, even if your scout says he has 4* PA, forget about him because he will never get to his potential (or possibly will but will have skewed attributes that inhibit him from playing his position well).
---------- Post added at 02:06 AM ---------- Previous post was at 02:00 AM ----------
One thing to note is, regens are actually created in Argentina on 1 July not 1 August, at least in my game.