The problem with saving all of your stones for the later Dokkan fests is that you probably won't have the units that you need to get the medals. I got lucky with some Niche cards to make a solid INT team that Stuns+Seals supers constanty (INT Dabura lead, INT Piccolo, Gen. Blue, INt SSj Bardock, INT Perfect Cell, AGL Golden Freeza, Buuhan friend), but it would be way easier if I had a god lead to work with. It's the main problem with the power creep for me, at some point I feel like I might have to reroll to get stones to get the best units because it's getting harder and harder to do any of the more difficult events without these gamebreaking units.