Actually it would be calc in ninth for the top cluster group and an exposure to pre-algebraic concepts for part of that group earlier than fourth in a reverse spiral because some kids drive better towards bigger concepts. If forced to cluster, I would design the top cluster such that my DS8 would have a place.
In a sane design for a gifted class you should be able to cut 30 days of beginning of the year review and 30 days of eog test prep. That alone would provide 50% more actual instruction in the school not accounting for other topical acceleration through reduced repetition.
