There is a problem with this site provably fair engine and i would like to talk about it with the community.
The provably fair engine works fine, but the fact that they use a new server seed for each bet make the game kind of rigged. The right way to work it is to have a server secret seed and show the hash to the user, and when the user request a new server seed we should be able to see the past one to verify our rolls.
I know we can see the hashed seed from our next bet, but if we don't change the user seed the server will know the result before the roll and that way he could choose if we win or lose on the next rolls, we could get a 'bad streak' generated by the site.
And there is one thing we can do in our side to avoid this to happen, and that's to change the user seed on each bet. But this solution is a complex task for the user if he want to place a big amount of bets. Maybe a betting bot can do this magic.
You can't do big amounts of bets on the free rolls game, you need to wait one haire before each rolls.
And for the hi-lo game what you say can't work because the house don't know if you will choose HI or LO at your next roll.