They'll go zeropod and nail it, they will outclass ferrari with a RB/AM sidepod and mercedes with a ferrari sidepod.
Honestly, I think you can learn most from how the car was adapted and then envision where they were limited with the current packaging. They've maximised the undercut of the sidepods and worked the rear of the engine cover/cokebottle. That's where I suspect they will do some repackaging for more extreme aero.
They also might take their aero concept to another level with yet some form of innovatieve concept that will shock us when revealed, but I doubt they'll risk it.
Additionally, this year has proven how much aerodynamic frivolities are allowed. Especially merc have been trailblazing some aero thay I am surprised they were allowed to keep. Also more and more small wings around i.e. the AM cockpit. All cars were rather clean coming into the season and nobody dared depending on them. As it is now more clear what aero will be allowed, they are probably going to be a bit more fundamental to the chosen concepts.