I'm not convinced about using higher value resistors.
With 1k & 330Ω across 14v, it's only dissipating ~150mW, well within what a standard ¼W through-hole resistor can handle, though a bit much for a standard 0603 Thick Film SMD Resistor ±1% 0.1W.
The OP states
I am trying to monitor a remote 12v battery
To me that means there's a long distance between the battery and the Pi, with all the problems of interference along the way.
As the resistor values go up, so do the problems, so I would be considering reducing the values, not increasing them.