We have used Take Off CS22 most of the season, but tried others, including the RP24.
As it's heat range indicates, the RP24 falls between the CS22 and the CS27. It does this on the track too. The CS22 gives a bit more grip, the CS27 a bit less.
So now basically you have an in between tyre too - just to complicate the issue.
Has anybody tried the new Powers tyres ?