Duct tape can fix anything, even an aerodrink bottle! I put a few overlapping peices of tape across the top so a little hole is left in the very middle. That way I can shove a water bottle into the hole and squeeze the contents into the bottle and discard the bottle or put it back into the holder. I like to race with concentrated electrolyte drink in two shortie bottles in my behind the seat bottle launcher. (actually doesn’t launch the shorties and that’s why I use them instead of tall ones.) I shoot 1/2 a bottle of concentrate into the aerodrink and top it off with water from the aid station. Takes about 10 seconds to refill the whole thing.
Get the bracket and ditch the rubber bands. They will break one day and you will be pissed if it’s race day. About $12.00, worth every penny. I too kept the yellow fishnet roll of plastic inside to keep the sloshing down…
Happy racing - Karma