Academy to Coaching

For those of you that've been around a bit longer, I've finally managed to get my player mill online with 6 coaches and 10 player spots, so I was wondering what's the approximate optimal time to switch a player from Academy to Coaching, assuming a 13/100k/1 Academy system. When does the trade off of guaranteed skill gains for Champion Mastery and slightly less optimal player stats become worth it?
Optimally they don’t even spend a day in academy, you promote them right away so your coaches train them instead of flat gains from the academy system. Academy gives decent stats to the position you assign, but half stats to every other skill which means even really average coaching is better than high investment academy coaching.
Ah, I didn't notice it gave half stats. Thank you for the advice :)
Wow mind blown, I was wondering how i would get an economy going where i could comfortably afford a 100k a day additional expense but paying a million just once for a 13 year old and coaching them straight away seems a lot more achievable.