It is regal riches. reset is 5 30 40 50. The easy play is when the blue gem gets to about 9 (I don't know how it can go it got to 19 once for me).
The 30 becomes a must hit by 75, 40 mhb 100 and 50 mhb 125. If you are playing for the bottom right alone I would suggest somewhere around 53 or more.



The payouts in the bonus game aren't great even at the top numbers. I have hit the 75 (at 76 and 78 over the mhb amount) and not gotten back $100 on .75 a spin.