My best while being accurate with Hi-Opt II without Ace was 9 seconds, but I averaged around 12-14. I hold the deck in my hand with cards face up and push them off with my left thumb. Although, I do agree with others that this isn't a good way to practice. You need to practice making all the plays/bets which includes TC adjustments and Ace adjustments for ace neutral counts. Oh, and also talking at the same time

. It took me a year or so before I could talk and play accurately

.
Best,
Beast