The Tiggie had extreme differential...something like 1/4" down, 3-3/4" up.
I've used 100% differential... no down at all... on some of my Lifter airplanes, which fly in the tip-stall area all the time.
No down aileron prevents tip stalls due to aileron deflection.
.
"..no servos, just the pilot's hands and feet."

Imagine flying something like an Eindecker, with the full flying tail surfaces, which had to -held- in the trim condition all the time!