With the season planner, you can:
Assign goals to any rider
You have to assign 3 goals to a rider, else it will not work.
A rider who has 3 goals will automatically become a leader.
If you remove all 3 goals from a leader he will become a helper.
If a leader becomes a helper, he and his helpers will be distributed to other leaders, you can re-arrange the helpers in the game.
Select any race as goals
I did not test this fully but at least the game does not crash if the goals are not assigned chronologically or all goals are in the same month.
I still recommend that you select one goal for each period.
Change the race calender
You can change the race calender for the team and each rider. The planner should use the same rules as the game, so you cannot ride the TdF with a Conti-Team.