A833 OD or 727 behind a 440. Suggestions and questions

I think in this case, the manual would do it for me, but not with a performance rear gear. The od gear in that box will not take any shock-loading. So with a performance gear you could easily forget that when banging gears. But the od gear could help the motorhome engine pick up some fuel-economy, if it's idling down the hiway. And the 440 has way enough low-rpm torque that it doesn't need the big-number gear. In this way the big 1-2 gearsplit will be less noticeable. What gear then? That would depend on your tire size. Mostly.
Probably a gear to put the 440 at a favorable rpm at 30mph in second gear.
But what's back there now?