In this case here this 376/410 you'd probably have to go one maybe two gear ratio deeper than what you'd put behind the 410 to be putting similar HP to the ground.
The simulation I ran resulted in 3.71 gears for the 410 and 4.11 gears for the 367, and they were close. So I think you are right in this case
But after running the simulation where I moved the HP curve up 1000 RPM's and wasn't able to get close to the performance of the lower RPM 367, I think gears aren't enough and your theory doesn't bear out.
BTW, the 8HP simulation and 2.65M iterations was a bust, couldn't get close to the performance of the 727 setup. I wouldn't be surprised if my slip percentages and such make it an invalid test though, the simulator just isn't sophisticated enough to make it work. Plus the gear ratio's don't make it a slam dunk either, with a 4.71 first gear and a 4.11 rear gear, the result was the trans was in 1st for 0.000 seconds, or such a short time it can't be displayed in the output. More gear splits have to be an advantage, but I couldn't show it with the tools I have.