I completed yesterday the first set of the new years event. I'm now in phase 3 of 36. 1st stage is not that hard, but takes some time and gives 200 tokens for the 1st booster. The following sets are..... alot. My problem is that I have to wait for 2 days now, in the weekend, to get started with the 2nd set.....
My conclusion is that it will take alot of time without the gold boosters and you shouldn't do a grind-only. Just playing and teching is better and less boring.