How much further can I go?

Very difficult to determine with the fuel bladder the way it is...the more you drive it the more closely you will be able to tell (and based on what mileage the pips gave you over the current tank). If this is a guessing contest...I'll say 80 miles to pushing your car to the station to fill up...30 til you're on your last pip.

But, best practice is to refuel with 1-2 pips remaining...no need to squeeze any extra miles out of a tank...what's the reward?

 

The problem is that the milage is going to vary quite a bit because you will not always get the same amount of fuel in the tank so the test is rather worthless for future estimates. It would only be good for bragging rights.

 

I just got my 2006 in March and had only 2 fill-ups in a row after driving down to the last pip before it started blinking. It took 11.611 and 11.625 gals so I think I can safely do this with each tank as long as I get gas before it blinks.