I know most advanced Cheat Engine users already know how to do this but I thought I would explain it to the new users who are still trying to figure it out.
The new event, "X Marks The Spot", requires you to play treasure hunt for rewards but this will also work for most events like this. I know a way to claim all the rewards in one Treasure Hunt game. Simply follow these instructions:
- Start a Treasure Hunt game.
- Make one move.
- Open Cheat Engine.
- Select First Scan, choose EXACT VALUE.
- Scan for the value "1".
- Go back to Gems of War and make one more move.
- Open CE again, select "Scan Type" and choose "Increased value by..." and keep the "Value" set to "1".
- Click "Next Scan".
- Keep making one move at a time and going back into CE and scanning for an increased value of 1 until you have only one or two found addresses.
- Right click the address that CE found and click "Change value of selected address". Type in "150000" (I know that seems like a lot but just do it).
- If CE found two addresses (sometimes it always finds two), change the other address to "150000" as well. When you go back into Gems of War and make another move, you will notice that up top the move counter (clock icon) has changed to 150,000~. That means it works.

Go back into CE and finish the game.
When the game is done, it will reward you with 15,000 of the items required to claim rewards (I can't remember what they're called lol).

Congrats. You now have enough to claim all the rewards at once.
I hope this helps people.