I doubt you'll get very far with Retumbo and 140's. Nosler lists 52.0 grains of H1000 as maximum, and shows it as 108% of load capacity. That's why Magnum works so well: You can get more in a case.
All of the suggested powders may have lot-to-lot variations, though H4831 tends to be pretty consistent. Nosler also shows 51.5 grains of Magnum as maximum, for 2597 fps from a 23" barrel. My rifle beats that by close to 100 fps with only 50 grains from a 21" barrel.
