I'm new to Diptrace and have been working my way through my first schematic capture and board design. I'm wondering what is best practice for layers with a circuit with multiple voltages? My circuit has 9V/PWR and GND, plus a +18V supply from a voltage doubler and VRef (also 9V) for biasing some op amps and jfets.
Currently I have internal plane layers set up for all of these, with copper pours to connect to the relevant supplies. This turns it into a six-layer board, which gets kind of pricey for prototyping, so is it good practice to have each supply with its own plane layer and end up with multiple layers, or is it OK to just have PWR and GND as planes and not for the other supply voltages?
Thanks heaps

Pat