Well, I have completed the Summer Cycle and I agree with most of the things mentioned in the other post regarding Summer Cycle. I think only "rich people" can complete the cycle early and even relatively old players wont be able to complete it. But the grind being horrible and numbing was not the case for me. I just created one deck and used it exclusively to complete the cycle. I mean, I created one and after multiple iterations I had a deck which was good (relatively) which I can enjoy and win games while also completing the Summer Quests easily and moving fast.
I used a Call Of Harmony deck since Crimson Curse gave harmony to ST. I started with the 10P Ihuharrax (or whatever it is called) to pull Dana/Quarex (or whatever it is called), but half the time it screwed and the rest of the times also it was not good. Then I removed the 10P relict and had only Quarex and realised that even at 11P it sucks and actually doesn't fit in any harmony decks IMHO and replaced it with Waters Of Brokilon. WoB is not nearly as strong as other 11P cards in the game, but still much much better than Quarex. Removing Ihurarrax helped me to fit in Gezzarz. This is the deck end I ended up with, with which I breezed through the quests and got the cardback.
This deck has 13 cards from Crimson Curse and WoW, predominantly from Crimson Curse. So, the quests I was targetting was mainly "Play x cards from CC or WoW", "Win after playing 5 witchers", "Win a game with at least 13 cards from CC or WoW", "Boost x units from CC (or WoW)", "Play x ST cards from CC/WoW", "Play x witchers", etc. I just kept rolling with scraps until I get one of the quests which my deck would easily satisfy and every time a quest is over, immediately unlock a new one and re-roll until I got the quest I wanted.
If you want to unlock the Holy Grill cardback, feel free to use this deck (if you like ST or have no problem playing ST) and follow the strategy. This deck is by no means strong or optimised. But you can get 50% winrate and if you are good/skilled you may even get more wins. Or you can have much more optimized deck (without meeting the 13 cards condition) and use it and have this or similar deck only when you get the 13 cards quest. I was too lazy and loved the challenge and used this deck completely. Good luck with the grind/hunt.
The deck once again.
I used a Call Of Harmony deck since Crimson Curse gave harmony to ST. I started with the 10P Ihuharrax (or whatever it is called) to pull Dana/Quarex (or whatever it is called), but half the time it screwed and the rest of the times also it was not good. Then I removed the 10P relict and had only Quarex and realised that even at 11P it sucks and actually doesn't fit in any harmony decks IMHO and replaced it with Waters Of Brokilon. WoB is not nearly as strong as other 11P cards in the game, but still much much better than Quarex. Removing Ihurarrax helped me to fit in Gezzarz. This is the deck end I ended up with, with which I breezed through the quests and got the cardback.
This deck has 13 cards from Crimson Curse and WoW, predominantly from Crimson Curse. So, the quests I was targetting was mainly "Play x cards from CC or WoW", "Win after playing 5 witchers", "Win a game with at least 13 cards from CC or WoW", "Boost x units from CC (or WoW)", "Play x ST cards from CC/WoW", "Play x witchers", etc. I just kept rolling with scraps until I get one of the quests which my deck would easily satisfy and every time a quest is over, immediately unlock a new one and re-roll until I got the quest I wanted.
If you want to unlock the Holy Grill cardback, feel free to use this deck (if you like ST or have no problem playing ST) and follow the strategy. This deck is by no means strong or optimised. But you can get 50% winrate and if you are good/skilled you may even get more wins. Or you can have much more optimized deck (without meeting the 13 cards condition) and use it and have this or similar deck only when you get the 13 cards quest. I was too lazy and loved the challenge and used this deck completely. Good luck with the grind/hunt.
The deck once again.