Making $700 in a week is a myth or luck with low lotsize.
But making money is possible with any strategy using risk:reward ratio.
There are people who only make money using risk reward ratio with any strategy.The Proper risk:reward ratio clearly depends on your strategy. If your strategy has good winning probability, you can even go for 1:1 ratio.
I use keylevel breakouts strategies for risk reward ratio.
The probability of my strategy is 60 to 65% atleast. Based on this I decide the strategy.
You can check the full research on The Plan how to make money in forex using Risk reward ratio with any strategy.