JE Custom was doing this years ago on device he designed to test brakes.
The different powder causing more or less recoil is almost entirely a function of the mass of the powder. A reduction in the mass of the powder for the same pressure will always have less recoil. Velocity is time under that pressure curve so equal pressure might not equal the same velocity, depends what the pressure curve looks like.I think if you used the right powder (not the same powder) for different bullet weights, to get same load pressure, the recoil differences would follow bullet weight more closely.