This is just me, but I'd go with the Williams 5D. Get it dead on at 25m for windage and elevation. Then go to 50m and 100m, but don't adjust... just see what kind of drop/climb there is on paper. Then shoot/sight-in so elevation is dead on at 100m and shoot the other closer distances again to see what it does. Just what I would do.
As for ammo, whatever good stuff you buy, you can never have too much, but you can easily have too little.