hole carding Texas Bonus Poker - whats my edge ?

I know of a couple of casinos where is possible to see one of the dealers cards and one of the three flop cards in Texas Bonus Poker.
It takes a bit of patience as the right sloppy dealer has to be present and a specific seat has to be available.
One casino has Vegas Rules and the other has atlantic city rules.

I wrote a complicated simulator in c which seemed to reveal a large edge to the player with this info.
Based on that I played for a couple of weeks and things went well. Then in one single day I went on a sickening run of cold cards and lost all my winnings and a bit of my starting bank.

I began to think that I must have made a typo somewhere in my program. It seemed very improbable that I could have a day like that if my edge was large.

I was thinking about starting from scratch and error checking my simulator in detail so I can take another shot at the game.

Before I do. I just wanted to make sure I was heading in the right direction.

Does anybody have any info to share about this game. Is there some way of getting a rough approximation the player edge by

a) knowing one of the dealers down cards during the game.
b) knowing one of the flop cards before placing a bet to see the flop.