heres an ammo can on one of my bicycles . ( 50 mm and grenade can )
just painted it black and stuck a sticker on it .
mine is not bolted on .. it slips over the back tube so i can just grab it and go . Holds 8 tall cans . the box is a bit wide though . i would go with the narrower box . Its a bit heavy ... next time i,ll use a hello kitty lunch box .