What's an acceptable ROR? 5%,10%, etc.
how can one avoid or limit to a minimum the frustrating fluctuations (SD)? I prefer making less profit per session and make sure i don't go through violent deviation swings.
That is up to you to decide. Most Pros play with less than 2% ROR, but then they are looking at having to get a real job if they go broke. Some people have what they call a 'hail mary' bankroll. They play with 20%-25% ROR, and if they go broke before doubling it (and then playing with more reasonable risk), they simply quit the game until they can rebuild another bankroll. I would think that anything over 10% becomes almost certain doom if you play for any length of time.
Ways to reduce variance: smaller bets, larger bankroll are obvious answers. Be very disciplined about wonging. Only enter games when you have an advantage, leave as soon as the count is negative. The smaller the number of decks being used, the less the variance. Spread to 2 hands, betting only about 70% on each hand of what you would normally bet on 1 hand. Don't play marginal games. Seek out good edges. Avoid trying to grind out a poor penetration game.
When you win and make a big increase in your bankroll, don't resize your bet unit and start making larger bets, use these winnings to increase your bank size and reduce your ROR. On the other hand, don't reduce your bet size if you have lost a large portion of your bank. Resizing your bets after losing 50% bank will reduce ROR, but it will also take you much longer to dig out of your hole.
Learn to hustle comps. Get cash back from the casinos. Enter every free promotion, tournaments, and take them up on all offers. Reduce your expenses, eat and drink on the casinos tab, not yours. Free food, Free drinks, Free rooms, Free entertainment, and other free perks can be looked at as contributions to the bottom line.
I would not be happy with more than 2% ROR. It is definitely a personal thing. Sort of like different investments, some have high risk but offer high returns, others are low risk, but you have to invest more to get a decent return.
>how can one avoid or limit to a minimum the frustrating fluctuations (SD)?
Wong and play games that have surrender. These two will decrease your SD substantially, while only mildly increasing your EV. The net result is a much straighter road to the promised land.