[David Watts]

One thing you could do is pick a year to start, for example 2016. The inaugural draft for you league will feature 1320 random players at random ages(30 teams times 44 players per team = 1320).

Create your league.
Disable player injuries and the OOTP development engine.
Go to the rules section of your league and edit the amateur draft so it creates your desired number of players. Remember your teams already have enough players for 44 rounds, so if you have OOTP import enough players for a 35 round amateur draft, your league will end up with enough players roughly for a 79 round inaugural draft.

Now you want to fast sim the first season. Don't even pay attention to the results. Once the season is completed fast sim until you reach your leagues preseason. Once your in preseason, go to settings and erase entire league history. Then select the option for the game to release all players and create a fantasy draft.

The inaugural draft for your league will now feature give and take the 1320 players from the initial inaugural draft and the 1050 players you created for the amateur draft. So you will now have roughly 2370 players available to draft from. This would allow you to run a 79 round inaugural draft and have plenty of players to populate minor leagues.

Once you have run the draft you can turn injuries and the development engine back on and reset the draft so it creates less players for the rest of your leagues history.