I don't believe sliders will have any effect in this game. Fast sim doesn't load anything except the roster and coach profile (run / pass on offense and defense as well as aggressive / conservative) from my observation. Essentially, they take these coaching profile ratings and calculate the results based on the rosters. young22 mentioned the Awareness rating (which effects every rating for each player) which should be your first try. Another thing to try is the Throw Accuracy to increase / decrease the QB completion percentage AFTER you determine Awareness doesn't quite get you the results you want. Keep in mind that when you decrease the THROW ratings, your QB is likely to run more often which is why this should be your second alternative.