I've only just seen this but it might help out someone else searching for info.
Another easy alternative for colouring bare wood is calligraphy ink. Loads of colours, cheap, easy to apply and clean up. Just wipe on with a fine sponge. Being water based you can wet and rework if it's slightly patchy, even take it off to a degree if it's too dark.
Oil, varnish or lacquer will go straight on top without affecting it.
This a bass that I've just done, it was all natural wood previously.