After about a week of Tweaking I have finally settled on the configuration below and it is fairly stable witha reboot once every 24hrs or so.
This is using the modded BIOS trick and all the voltage settings as can been seen in the picture.
I have tried using drivers version 19.50 but got slower results by around 3 MH/s per card.
Using the latest 20 drivers from AMD resulted in my overclocks/undervolts not working and the hashrate being much poorer.