Hi Chris, I am at the same stage as you, got tracking pretty good for up to 60sec subs. Then I got myself an auto guide camera a couple of weeks ago and that's where things started going backwards. My guide star was jumping all over the place, a bit of tweaking with the settings tamed it a bit but not enough for what I was expecting out of auto guiding. What I have found after 3 nights of no results. It is really important to have the guide star well focused and of the right magnitude (not saturated ie. too bright) I then spent a while adjusting the worm drives on the mount and after a few goes found the sweet spot, not too tight or loose and the phd graph is looking a lot more steady. Now I have to play with the settings again to tighten the software side of the guiding. In my case soft focus stars were caused by the guide star moving around too much.
My setup is a Heq5 pro with a side by side RC6 (1350mm fl) and 120mm f5 (600mm fl) SW guide scope.
Guide to adjust the worm
http://www.astro-baby.com/heq5-rebuild/heq5-we1.htm
Guide to graphs
http://openphdguiding.org/Analyzing_PHD2_Guide_Logs.pdf