So without a custom ROM, i've had to settle with fine tuning WattMan. I'm happy with the final results. I probably could have undervolted a little bit more than this, but I wanted stability, so i'm happy with the current power consumption levels.
I'd like to thank @cpluscote
and the other users who have helped me to get to where I am now
3 x 480 PowerColor Red Devil 8GB, Windows 10 Pro, Crimson 16.8.2 hotfix drivers, Claymore v6.4, ETH/SIA dual mining.~28.1MH ETH and ~435MH SIA per card
Time for me to catch up on some sleep