The number of decks does not matter.
42.9% Wins with S17 [slightly lower with H17]
8.9% Pushes with S17 [slightly lower with H17]
So that is to say you have a 51.8% chance of winning or breaking even. Which of course does not warrant going against a 48.2% chance of losing. It just goes to demonstrate why counters wait until the likelihood of better-paying naturals is highest, as well as the chances of winning on doubles and splits, before raising their bets.
The number of decks does not matter.
42.9% Wins with S17 [slightly lower with H17]
8.9% Pushes with S17 [slightly lower with H17]
There is no significant difference that I can see.
My question for you is — why would there be ?