I have the G4 7/9 and use it on my Grey's 10ft 8wt and my Loop Cross S1 switch rod. Perfect on both with regards to balance, but it also holds a fair amount of backing for Salmon/Sea Trout fishing. Highly recommended.
The G4 is significantly heavier than the general run of reels in this size category, e.g. Lamson Guru about 220 grams, the G4 is about 275 grams, so it would be a good idea to check your switch rod to identify the optimum reel weight for it.