I think I'm closer to 45min-1hr, but I spend a lot of time trying to maximize hits on the opposition. I might need to move it from Medium to Hard, though, because (although my offense still putters around some) my defense rarely gives up a score.
With that said (and because of the picture a couple posts up), does anyone have a good website for cage descriptions and theory. All the ones I've found refer to pictures that don't exist anymore. I started with a full, tight cage where my guy was completely surrounded on all sides...while that was safe, I'd get trapped a lot and moving the ball was too slow. So, the last couple games I've went to the X cage, with one guy on each corner. It works fine, but it seems like there should be a better way and I want to see if something else is out there before I sit down and plot something out myself.
Now that I have a thrower and a couple good receivers, this isn't as much of an issue, but for a pure ground and pound team, it's essential.
Hard is widely regarded as the easiest difficulty setting, because hard actually adjusts the AI to be more conservative and more risk averse. Therefore, if you apply a lot of pressure on them, they're likely to run backwards rather than forwards, because they don't want to lose the ball. They're also unlikely to try a 5+ pass that could change the game, for the same reason. Try on easy, it's the most risky AI set -- they aren't deterred by making multiple dodge rolls every turn and making risky plays. Yes, they fail more, but they will also catch you with your pants down from time to time.
All that being said, having played you already, I can see you're at a skill level where playing the AI is just fun, it's not going to improve your ability too much. You'll get the chance to try out new skills and different builds and create just awesome teams because your best guys will never get targeted for execution and gang fouls, but there's a tactics level for beating the AI that you've already surpassed.
As far as cages go, you don't want one that's too tight. The full cage (ball carrier completely surrounded) isn't that great because it's real easy to push a corner, and then chain push the ball carrier out of it. The X cage is probably more widely used -- provides some wiggle room for pushes, and with Guards on the corner, it can be pretty well unbreakable against anything other than a leap, stunty wrestler, hypnotic gaze, or the rare 5+ str break tackle guys. Also remember that the more guys you commit to a cage, the less you have out in the field tying up other players. If you've got an X cage, the opponent should have you outnumbered 11 to 6 elsewhere, and that's not always that easy to advance under. Be mindful of where your opponent can get to and where he can't...if he can't get to the back corner of the cage, you don't need that guy there, he can be providing assists elsewhere.
The better way you're looking for is probably the screen -- just place guys in a wide arc, 2 squares apart, and maybe a couple rings deep. That way, the opponent has a choice of blitzing a hole in the screen, or having to dodge to blitz your ball carrier. It provides more room for mobility, at the expense of if your opponent gets lucky with a cas blitzing the hole, he can potentially get a lot of TZ's on the ball carrier, which leave you with shitty decisions -- dodge or pass in TZ's.
There's not gonna be one sure fire "Best" way, because both have their weaknesses. Which is good for the game, actually.