I used "deposit into bank heist 1" strategy by depositing $25 with 20% and 30% with Vegas Regal and Tropica casino, it worked great, I won the max bonus amount of bank heist 1, but I was greed, I played other games, hoping to win more, and lost eventually.
I found a new rival casino, Riviera Royale, they had a nice first welcome bonus of 150%. I claimed this bonus with $50 deposit, but I had "no promotions available" after my deposit was made. This was probally because my account was flagged across rival system.
I found that slots are usually loose at a rival casino that I play it for the first time and it was the same with Riviera Royale. I had a bonus round during the 10 free spins of Candy Cottage game which won me big and I won big with Bowl Over game later (see screen shot), I could have walked away with $950, but I kept on playing to see if I have anymore luck and I cashed out $800 eventually. I hope we will affiliate with this casino in the near future and zuga can bring us the exclusive bonuses.