You may struggle with making 20 teams because of the inability to edit nationalities. Me & my mate usually do a ML with Championship teams (Although we couldn't on PS3 last time, just PS2.) Our way around the issue is we're only going to make 14 Championship teams (+ 1 team to do ML with) & just make ML D2 League have 14 teams in it. Then just add a few players from other teams not on game to bulk up the transfer market. I've already collected all players stats (height, weight, pos etc) & a pic incase I want to put face on him. And I've got stat converter to convert FM to PES. Just updating all stats from FM2010 at the moment. If U think they'll be handy I could send them U. Also kept a note of players stats who have previously been on the game.
You can edit nationalities this year :w00t