I ran with all 20s until the last round of seasons. Now I am dropping them all to 0. This is based on some of the things I have been reading on the Forums.
Here's why -
To me, unless you intend to do a lot of trading for other team's prospects, ADV makes no sense. If you have a very good scouting budget, and do your due diligence, you know what a drafted guy/IFA's ceiling is. The next 3-4 seasons, you make sure the player plays often, moves up regularly, and has good coaching. When he's there he's there. A lot can happen in between where he - doesn't - get there.
ADV seems to be accurate from $16 on up (although to be if you are going to hit $16 you might as well go $18 or $20). So for purposes of your own prospects, all you are using ADV for is to monitor their 'current future' progress. But you already know what they - should - be capable of getting to from your draft/IFA results. And you already know where they currently are. So whats the point there? Use that $16 to $20 for IFA bonuses or your BL roster.