The good thing about the covet up button is your RB will actually breaktackles sometimes. But yeah you have to decide if you want to fight for more yards with the right analog stick or be safe and cover up..
Auto sprint off will help your run game out a lot. For some reason the defenders start reacting to the ball carriers quickly once the ball carrier is sprinting. With the sprint button off you can take your time with the cutbacks and hit the sprint button when you see the open lane. Don't crash directly into the line when you get the handoff. Look for the open hole and where the flow of block is going then hit that lane. Check the replay of all your run plays and I guarantee you will see open lanes you could have cut it back to. Let me know how it goes.