Welcome at HSO Christian
Its 99% sure our GP79 series will be back next season. Read the rules carefully, I think that will answer most of your questions :
http://historicsimracing.123.st/1979-f1-world-championship-f1/2010-rules-reglement-t607.htm
Its an historically accurate series so you'd drive for the same team during the whole season (only drivers on very slow cars are allowed to change when a good car becomes available).
You can already race as a wildcard if you want, you can take somebody's car if he's absent. As you won in other leagues, I guess you must be a pretty good driver so racing this year would help us to know what car you'd be allowed to drive next year, as we put fastest drivers on average cars to level the competition.