Also should note that if you have access to an already cycled tank, adding media from that tank is a proven method to speed up the process.
Off the shelf BB is intended for adding the fish in immediately. You are saying you can add raw shrimp and then put the fish in?I dot not be leave in any store bought cycling kits, I always cycled with raw shelled shrimp in a bio bag and let it run, no it never stank. Can do the same by just adding fish food to the water from time to time. and just let it run.
if you have bio Medea already then are ahead of the game and can get cycled sooner or you have enof and bio load low you are good to go.
Off the shelf BB is intended for adding the fish in immediately. You are saying you can add raw shrimp and then put the fish in?
Well the OP was asking about off the shelf bacteria. If doing without fish I would just add ammonia.No let the shrimp decompose it will produce ammonia starting off the Nitrifying Cycle. Monitor the water parameters until they stabilize to zero Ammonia zero Nitrite and Nitrate reading is positive. Then you can add fish gradually.