From
http://www.wizardofodds.com:
Expected Value by knowledge of first Card — Eight Decks
Card Banker Player Bet
0 0.055215 -0.079975 Banker
A 0.053624 -0.078313 Banker
2 0.049105 -0.073647 Banker
3 0.042813 -0.067164 Banker
4 0.032266 -0.056243 Banker
5 0.011320 -0.034723 Banker
6 -0.029691 0.007562 Player
7 -0.094126 0.073651 Player
8 -0.191207 0.172935 Player
9 -0.23249 0.215281 Player
All things considered, the player advantage, if the dealer always flashes, is 0.067647.