Hey Andy,
I would second any suggestion of investing in some Colortone from Stewmac. I bought some 2 years ago and the bottles are still going strong after over 10 builds. They are also really nice to blend and you can control the concentration perfectly. Black colortone may even cover your side plug sufficiently with a couple of coats without the need to spray (which will be difficuly to blend with the top). She's looking good anyway. I recokon one of these axes with a burst is going to look awesome, so keeping your build subscribed for updates!
cheers,
Gav.