You can use BB with the super magic but it will do little to stop the crystalization in the depot.
PEG is very water soluble so it will still leave the depot very quickly and cause crystalization.
BB is really only good when used in conjunction with another co-solvent and oil as the main solvent. As BB is more oil soluble than water soluble.
Keep in mind that the crystalization that happens in the depot of a supermagic/PEG solution is no worse than the crystalization that is already present in a water based suspension