Hi 
Off the top of my head, I’m thinking of a slightly PG heavy, menthol, cooling flavor profile, and some kind of tight pod system, though I guess that’s not an option.
But you can also play around with the coil build, for example:
Thinner wire, smaller core size, more wraps = smaller surface area → higher resistance, lower wattage = less e-liquid consumption, more economical use.
Then you can also vary the TH with the coil position. The higher you place it, the greater the throat hit. This might help boost the sensation enough that you can reduce the nicotine level a bit. If you combine this with some cooling flavor (if you like it), that can also improve it, and you’re pretty much there.
It might also be worth adjusting the airflow. If the airflow is a bit tighter, that also increases the TH and atomizes less, so it can be more economical. Though this is fixed with Dvarw.
I’m not saying it will last a week, but you might be able to slightly reduce the nicotine and consumption. 
Of course, these are individual things, I’m just writing generally, hoping something might be useful.