I tried the optimal method on 40 hands on unlimited blackjack online, straight bet 5$ each and betting on only one hand per turn.
Won 17 hands (42.5% - lost 7.5$),
Number of times the optimal method made me win: 1,
Number of times the optimal method made me lose: 4.

Then, I decided to get back my money with one win on progressive bet starting at 10$.
- first bet: I got 19, the dealer got 20;
- second bet (20$): I got BJ but the dealer also got BJ;
- third bet (20$): I got 13 and the dealer had an As. Odds were against me but I decided to not follow the optimal method. Players who took another card busted (it was a King). Finally, the dealer busted as well. Luckily I didn't follow the optimal method, it would have been the 5th time I would have lost because of it.

Total win for the session: 2.5$