I'm glad to hear the project worked out, and hope the end result is what you desired.

What all these calculations seem to ignore is that a 100 pound rider and a fit 200 pound rider can put a huge difference of force into the pedals.

So, the 100 pounder may need a low gear to spin.
The 200 pounder would need significantly higher gearing, even if they're spinning.

And, not everyone can maintain maximum power at 100 RPM.

Like you, there are also intermediate steepness hills that I spin out on. A good tuck might take less energy, but wouldn't speed a person up.