I'm using the Chargers for my fantasy team but running a 46/4-3
In the strategy menu, the amount of "slots" to configure are stuck as whatever they are when the game was released, 3-4 teams are stuck with 1 DT slot and 2 MLB slots, the opposite for 4-3.
But the 2nd slots configuration has no effect on how the players are rated.
For example if you set WR 1 as speed, all receivers will be rated as speed receivers regardless of what you set the WR 2 slot as.
The real question is if my 2nd DT gets less XP then he should because there is no 2nd DT slot, so less XP than he would be getting if my team had 2 DT slots to configure.
I have no idea to the answer to this, someone may want to tweet or email or whatever to Ea.
I'm probably going to switch to a 3-4 next season and move Suh to DE and possibly Poe as well (traded for Jesse Williams NT) so that they're both in a "1 slot" if it makes any difference for XP.
Plus the pass rushing has been pretty bland from the 4-3. My DEs Ansah and Jordan crushed the sack record cause my team and D is beast but there's not really any line stunts or twists, the DEs just try to run around the corner and the DTs just bull rush and even when they push the OL into or even past the QB they don't even try to get him.