FX:GBPUSD British Pound/U.S. Dollar
Different pairs have different behaviors... Also time frame considered and time that you trade (Australia, Asia, London, US,) You need to take all this in consideration and then perform Back Testing. If you are planing let's say to create 9 currency portfolio you should probably test 15 currency pairs and pick 9 (or as many as you can handle) that perform the best. You need to record every single pattern that you are interested in trading (Bat, Gartley, Cypher, Butterfly), winners and losers on a specific time frame (let's say hourly chart) and specific market that fits your lifestyle and availability to trade. You have to go back as far as you want/ makes you feel comfortable. Based on your results, you will see if that particular currency pair is profitable with that particular time frame with advanced pattern trading. If you want to check any other time frame (15min, 4hr...etc, you have to repeat all as mentioned above :-).