it's just bad to increase the fight's duration. the longer the encounter lasts, the more bloods spawn. that's also why you don't do multiple rolls at the start, you just waste time. the only difficult part is to sort out getting rid of bloods between plates by rolling off amalgamations and handling the bloods between 5th and 6th tendon. delaying the fight makes all of this just more annoying. as multiple guys wrote in this thread already, the key is to get everything done as quickly as possible and not waste time.
don't look for ways to increase the fight's length, look for ways to decrease it instead and you'll get it down much easier.