All of your answers can be found here:
Acceptable Helmet Certifications:
CLASSING NOTE: We reserve the right to combine under subscribed classes for scoring, or split over subscribed groups for the purpose of event operations.
For scoring, any group with less than 3 entries will get bumped in a larger class. Street Prepared > Street Mod > Modified/Prepared. CAM / SSC > Street Touring.
For run group purposes, Street would be split into S1 (SS, AS, BS, CS, ES, FS) and S2 (DS, GS, HS), but still scored as a single Street class.
If any group of competitors want to be split into their own class, you must have at least 3 competitors at each event to be eligible for a season championship. Please contact me for details.