Mornin
I still feel the O3G is a great tarmac and sprint tyre. The choice at the moment really is only between the Dunlop and Yoki Advan A050 (although, I'd love to do some real testing of the Federal FZ01 is I had a budget!).
THE Dunlop to choose for a GTR is the "R", which sounds like you've used. Not quite sure why you tore them up so badly, maybe someone familiar with the roads in WA can shed some light there? (1,300 Competetive kays is pretty bloody good though!)
With the event (Big Targa) now allowing you use 6 tyres instead of just the 4, the tyre issue is much less now, so, even treated a little harshly, O3G R's will get through no worries.
As you say, managing them is the key, and there's a heap of guys (some are even quick! ) within this forum section who are willing to share their experiences.
You're welcome to PM me for my ph # if ya want to yap when you're back from getting "massaged" in whatever Asian country it is you're visiting......