Any hopper will be fine with a mini,
if you want a hopper who don't decrease the mini rate of fire, just use a high-end force feed hopper, like halo (v35 will be great), empire reloader b or b2, magna, dye Rotor, Dxs Pulse, ....
A mid range hopper like an egg is good but less reactive than you mini and it will decrase you reactivity, without decrease the rate of fire ....
Choose your hopper for what your are waiting for, don't spend money for a expensive thing you don't need, and don't spend money in a bad hopper you will change after two games.
Thib