Sorry to get back to you late because my girls are always

the priority during personal time (grin).

You are right about "two-gap" defense. DL needs to control the OL so the LB's could go unblocked to the offensive backfield. You don't expect DL to have a lot of sacks or tackles in this style of defense.

One gap scheme requires slightly small DT who are faster and can penetrate into the offsensive backfield. So DT's in this style of defense tackle and sack more often.