Yet, in real world testing... I would think the measured differences would be relatively insignificant.
I think that no smart or expensive efficiency solution can beat the man driving the car. I mean, a driver with range in his mind and knowing how to get the most out of his battery pack will win it from a more efficient setup with someone who doesn't care.
But if you care, I think the most important thing to consider is peukert. If you're considering lead accid. If you're thinking of Lithium it is less important. But with lead it is crusial. A bad sized pack with fo example 50Ah batteries will not have half the range of a 100Ah pack, but maybe only 25%. If you pull to much Amps from a lead accid battery it's potential energy will be reduced significantly.
So calculate your power need. And choose batteries that can deliver those amps easy.
Again Lithium doesn't care much for Peukert.