The L1011 max weight I think is 211 tons.
And that of MD-11 is 285 tons.
Airliners wound't use only one engine due to ETOPS, safety, performance and reliability issues.
Sure. That is why 2 is the minimum. But a plane with 1 engine out of 2 inoperative has 1/2 the total installed thrust, whereas a plane with 1 out of 3 inoperative has 2/3 of total and a plane with 1 out of 4 inoperative has 3/4 of total.
Isnīt the maximum size of twinjet defined by what one engine can climb out with if the other is inoperative? Rather than by the available total thrust of 2 engines?