Thanks for the feedback Humayun and Marc. Going by my initial research, the QHY8 seems most suited to my setup. In terms of my mounts tracking, I have never really "measured" it. I know when I run PHD Guiding, when I look at the graph, the oscillation index is sitting on around 0.3 to 0.4 (I cannot remember the units). Will need to pay closer attention next time.
Cheers guys,
Daniel