What we know so far is available tuning is 7-8-6-7 adding ~9.3 PR to base car stats. This is another clone tuning pack very similar to British (8-7-7-6), Austria (7-7-6-8) & Abu Dhabi (8-6-6-8)
Update 27/12/2020- Contrary to muddled patch notes it's a fixed PR event and rewards are half those in patch notes.
Some charts below:
Think it's best to use an already upgraded car, minimize tuning and pick up the 100 Gold (quite good) and some driver XP along the way.
Recommend to practice the Spanish circuit in the Championship Series over the next few days when farming, as it is a new track to F1 2020.