Sounds like you NEED to read up on voltage to resistance. It looks like you think switching the "type" of coils is going to fix all your problems. The TRUTH is that you NEED to learn voltage to resistance to get a good vape. You need to learn what fixed voltage is, or what running off a battery is, in comparison to running a VV or VW battery. Your eGo, depending on the brand, is either fixed voltage, or it's just running off of whatever the battery voltage is. The only FIXED volt batteries out there right now are the K-go, the Go-Go, SOME Janty eGos, and I'm having trouble recalling the others. But my guess is that you don't have a fixed volt eGo. Ur prob running off strait bat power.
Since your running off bat power ur basically hovering around 3.5 volts for the majority of your vape. With a dual coil at ANY resistance, your going to need at least 4-5 volts. You can't access 4-5 volts. You can access 4 to 3.2 volts, no higher. So you need to stay away from dual coils all together, and you need a resistance that'll work with your battery's voltage. Around 2 ohms would be best. NOT DC. Just 2 ohms, 1 coil, thats it. No lower. No higher. You can try 1.5 ohms, but it'll increase your risk of breaking your battery.
You need to double the number of the resistance/ohms of your coils for your voltage. IE: 2ohms- Good at 4 volts. 1.5ohms- Good at 3.5 volts. With DUAL COILs, you have to quadruple the ohm number. 2 ohm dual coils- Good at 6 volts. You cannot get 6v from your eGo batteries. Your eGo batteries come fresh off of the charger at 4.2 volts, quickly drain to 3.5v, and then they end up at 3.2 volts when they need a recharge. So your resistance/ohms NEED to be around 1.5 to 2 ohms.