You should be comfortable with your 6-count double time Shag basic and have explored some Shag rhythm changes like repeating slows and repeating quicks. You have a decent range of fundamental moves you are able to execute and you have had a reasonable amount of Shag social dancing. Please have at least 20 Shag classes under your belt before joining this level.
You should be very comfortable with your fundamentals and you can Lead/Follow Shag rhythm changes in your sleep. You have a good deal of Shag social dancing experience and you are comfortable dancing to faster tempos over 200BPM. You should have at least 40 Shag classes (some at an improver/intermediate level) under your belt before joining this level.
You are a seasoned Shag dancer with lots of Shag social dancing experience. You are proficient dancing with those at your own level in Shag, but also dancing with beginner Shag dancers. You should have done at least 60 Shag classes, several of which should have been at an intermediate/advanced level. You are ready for a real challenge.