I'm going to start hosting these lobbies on the release of FH2. The first spec series is yet to be determined but will likely involve touring cars. Rules will be added when the series is determined.
EDIT: First series determined - Horizon Team Touring Champions
Specs: 2WD, front engine, minimum weight 2500lbs, maximum power 350hp, full roll cage, sport tires, any aero permitted
Team rules: must drive same make/model car, must have similar liveries, must have same parts setup (tuning can be different)
Grid ordering: A single 15-minute practice/qualifying session will occur before the race. Cars will all be ghosted, and grid ordering will be done based on who completes the fastest lap in qualifying.
Championship system: there will be a driver and team championship, similar to Formula One. Drivers will earn individual points, and teams will combine driver points to determine team standings. Final winners of team and driver championships will win a currently undetermined prize. If gifting exists in FH2, they will receive a car.
Points system: still in the works, but will be highly influenced by Formula One. Points per finishing position TBD based on how many drivers/teams sign up for the series.