Here's what I did:
Search 3X4. That gives loads of results. So far the values for all these hacks have been over 1000000000 but below 2000000000 so what I then did was refined my search by doing >1000000000 and then again by doing <2000000000.
That got rid of a lot of results. I then changed a few screens and just rotated refining =3X4, >1000000000 & <2000000000.
Once it got to a point where the results weren't getting any lower (approx 1800 results left) I then filtered the results to 200 at a time. I then changed the first 200 to 9999X8. Then check to see if it changed. If not remove and try the next 200.
I got to a point where if I clicked on the gold cup the screen wouldn't open. So then I reverted those results and narrowed the filter to 50 and carried on the same process. Eventually I got to where the screen opened and the gems had changed. I did carry on narrowing it down until I had the exact value but that's probably not necessary.
If you or anybody else tries what I would suggest is only hacking a small amount. Maybe check what is the highest amount of gems you can buy for real money and try that amount or maybe even a little less.