At a 1.08 multiplier, with a success rate of 91.67%, you have a 50/50 chance to hit a red every 8 bets, making an average profit of (7*0.08)-1=-44%
0.9167 * 0.08 + 0.0833 * -1 ≈ -0.01 average profit, as is the house edge
Just spotted your post - had already made the corrections, but thank you nonetheless. Coming off a double shift with no sleep evidently impacts my mathematical abilities.