Thanks for the great advice guys on the sprockets. Based on the posts, I guess I'll try to switch the rear out to either 51T or 52T. My chain whilst still in good condition in terms of free movement of the links and no perceived kinking is at around 80% of max out adjustment so I figure it should stretch across even a 52T. However, I'll shop around to see if I can also pick up a 12T front sprocket and a 51T rear, just so I can play around and see what works best for me.
I read on the TT crossover thread that the DRZ rear sprocket is the same as the DRZ400 so that should open up more options for finding one.