EDITED** If torque peaks were published as an honest/horsepower number, diesel guys would be losing their religion. In a horsepower debate, peak horsepower, while only part of the story, is a more accurate number than peak torque listed for a diesel at an rpm that "feels good", but generates no more usable power than said gas engine at torque peak.**
That being said, the Yota would require, perhaps an 8 speed, to deliver the same performance, where the Cummins, given its lower operating speed, inherently requires less gear reduction, and less ratio spread. So in a consumer diesel, 6 speeds is probably close to ideal, (to many unnecessary shifts isnt good either), a gasser, 8 is likely ideal. The gas engine could skip 1st when not towing, and 7&8th while towing.