Lithium battery configuration on a 25" 2017/18 FC twin.

[n9hox]

This question is posted mostly to individuals who install Solar systems routinely or as a business.
I will be purchasing a new 2017/2018 twin bedroom flying cloud this November. And we like the front and rear bedroom model, turns out we can go with either configuration so the deciding factor will be installing lithium batteries approximately one year after purchase. So I'm going to let my decision rest with what people think would be easier and give me more storage for approximately 600 to 800 amp hours stored inside the trailer. Again the model will be the twin bedroom configuration flying cloud.
Thanks everybody for your opinions.