What sort of returns should I expect
3000$ worth of Bitcoin is a good investment try to put it in Moneypot.com and keep it in a month or a year. I am 100% sure that you will profit even in 1 week. But of course it is all up to you. Goodluck
there is no guaranteed return since you are investing in a gambling site, players can win or lose depends on their luck. you can invest hundreds of btc and you can only profit as low as 1 satoshi from it in 1 month time, totally depends on how much players losses in the site and it will be divided to investors
They can set the rules on slots and video poker by using RTP and increasing the casinos win percentage but they must still keep this within a certain range that has been advertised to it's players or they are just cheating.
If set up correctly a bitcoin casino should not be able to tell when a jackpot on one of their slots is going to pay off and they must keep enough btc on hand for any big payout from such wins.
I don't think the casinos have an option to change RTP if using slots from providers like Softswiss but i may be wrong.