Smaller sails: Older cherubs were struggling for power much of the time, so the sails tended to be a bit full. We found handling in ballistic winds easier with the flatter and more adjustable bigger sails. On Atum with full cunno on the leech of the main would go floppy like a board sail. We havn't quite managed that with the new boat because the top cringle is too far from the bolt rope and mega cunno causes the top bit of mainsail to get a bit fuller than completely flat. Basically I don't think that slightly smaller sails makes any difference compared to getting the main seriously flat.
Self tackers on a tack: We ease off the jib a lot going upwind when it is ballistic, and especially in the run up to a tack. Stalling mid tack is something we seem to be getting a bit better at not doing, but it does still happen from time to time, especially in a funny short-chop seaway.
Backing lines: Pasta Frenzy had these, and we considered it, but Lucy can grab the jib car directly. One second is usually enough. I remember sailing Aqua with Cookie one quite windy day at Castle Cove and we couldn't get through the wind. I could not understand it. Later Lucy explained that one of the things she does in big winds is hold the jib car for a nanosecond to help the bow round if the tack is looking messy.