"Each side of the house has
30 rafter bays under the eaves, this would require installing 60
individual rectangular soffit vents. (I know about
continuous vents, but I'd like to stay away from them. I'm an idiot
carpenter, the less cutting the better).

Sounds like a good reason to use continuous soffit vents. They only
require two straight cuts the length of the whole run and are easy to
install.