If you were just looking for an example, I'd say go find Aserus. He carried SLX GST last season with the average landings of 8 or more. If you just look at his performance during the GS, he looks like a guy who has an average of 10:1 spar ratio.
Clops, he is a pure elite. He can be insanely good at teamwork. He looks like almost as if he was trained professionally for this. He's much more well known for high quality of performance during GS than the spar.
If you were looking for the opposite examples. Majin. Not a bad guild sparrer, but comparing to what he can do in sparring. He's not doing as well as he should in the guild sparring. Probably distracted in a tight space (when we failed to zone), he can't dodge and pull his skills off as much as he can.
Bob. one of the best counterstriker using the blink in single sparring. But it's not the same story in GS. Two guy jumps at you, no blink *** works.