There are plenty of good soccer opportunities with big numbers. A lot of times in Cup qualifying and such one team will bring a full squad and need a win while the other team is eliminated and looking at all players under 25 to see who can contribute next go round. South American qualifying is great for this, they have only one round with all teams playing and the last 4 or 5 games come up with plenty of good opportunities.
There really isn't too big a number to lay in my opinion, it is just that gaining true value out of a game at -500 is really tough. My biggest loss was laying -580. Still I have good records and can say my record in any sport of laying -400 or higher is a stellar 23-2! I might be due for another loss, but that still puts me way ahead for these big lays.