[RedDevil]

The limits on the G2's efficiency at low speed are both physical and functional. The RPM is lower at the same tpeed than with the G1, and the CVT will keep the revs at 1100 no matter how slow you go. When that happens the FE drops linear with the speed. Unless you can P&G.

At low speed air resistance is way less than at high speed, and so is the penalty for changing speed.
So I see no problem in my P&Ging at low speed. I get good mileage, even though the last 4 months were colder than average for the time of year. P&G plays just a minor role in that, but if you look at my record you will clearly see the point where I learned to reduce the use of the hybrid system.

It is great to use the EV mode when the battery is full, so if you can charge it by the mains or charge on coast where you'd need to brake otherwise, that is the best you can do. As you said, it will always depend on circumstances.
Trying to keep the battery full will make the system use it whenever it can, while if you draw it empty it will try to replenish it given half the chance.
If you want to stay in control you need to anticipate the chances you will get to draw or load; e.g. draw it empty before going down that mountain and keep it brimmed before going up.