Gains/losses are subjective, depending on what percentage they amount to. It may not be so simple to just say under/over
What's the goal, budget, what other if any mods have been done?
I've done changes with aftermarket/different sized supercharger and/or jackshaft pulleys that sped up the supercharger, which of course allowed it to build more boost. I have yet to change the crank pulley from stock, or use underdrives in any location.
Gains can also come from changing a pulley from steel to aluminum while keeping the same diameter. Some gains come from reducing driven weight and some from spinning the accessories slower. You essentially 'recover' horsepower, vs. simply adding more. The end result is the same, just arrived at it by different schemes.
Point is there are different reasons to change sizes up/down~under/over, and/or from steel to aluminum, resulting in different recipes/combinations, from those that are safe for and strictly used on the street, to others that are just for the strip/racetrack. What I'm happy with and what works for me, may be entirely different from your choices, budget etc.