The Six Line Quattro system is a variation of the Dozens and Columns Switcher. Be warned, this is a pretty aggressive system (in terms of the negative progression, which means the increased betting after a loss, in any case).
It does involve covering just under 2/3 of the table though, so the risk is managed down on the individual bets- it'sd a so called low variance strategy as opposed to a high variance strategy like the Single Column Roulette System which involves lower table coverage. It´s just that it involves a Triple Martingale progression, which can be pretty hairy, so look away now if you are squeamish or ultra conservative in your betting!
You cover just under 2/3 of the table by covering 4 six-line bets (6 numbers each- so 24 numbers). We like to play 6-lines that didn´t land on the previous spin, but you can just as easily go for repeaters and cover the six-line bet that includes the number that just came in, plus 3 others.
We´d recommend that you stick to one system or the other- i.e. fish for sleeping six liners or include a repeating one. It´s easy to be consistent during your session to help you decide on bets quickly.
Important. Don´t overlap your bets- only play mutually exclusive 6-line bets otherwise you will not be covering 24 numbers- you´ll be doubling up on numbers if you bet (1 to 6) and (4 to 12) for example. The idea behind this system is to get good table coverage.
After that- the system is very straight forward. You just need to ensure that you have enough bankroll to allow you to stomach 3 losses in a row (at which point you would hold up the white flag).
You play a Triple Martingale, that is to say, that you continue to bet at your original bet after a win (flat betting). After a loss, you multiply your bet by 3. We told you it was a steep progression. The downside of covering so much table, is that it is expensive if you lose all 4 bets and you´ll need an aggressive progression to claw back any losses.
Let's say you start off with a £20 bet, £5 on each six line bet. After your first loss you would need to bet £15 on each 6-line bet- a total of £60. A loss at this level would mean you would have to bet £45 on each bet, a total of £180.
So your budget to be able to play this system is £260 minimum.
As with all systems in roulette- you will hit the limits at some point. That´s just probability. You need to make sure you pull out before you hit 3 losses in a row, so set a strict profit target and stop if you hit it. If you can afford it, bet high to begin with and set your profit target at a modest % of your budget. That way you won´t have to stick around at the table too long, and the casino will have less time to claw your money off you.
As always, set yourself a strict stop loss (your 3 loss budget is a good one) and stick to it!