Well you'll surely get a lot of battery life with a 5 ohm build, but not a lot of vapor. Generally, lower ohms is going to give you all you want. Try lower ohms say 1.0 - 2.0 ohms, depending on how low your battery will fire (1.5 ohms?). Little heavier VG, say start at 50/50 or 60/40. More wattage with the lower ohms say 7.0 - 7.5 to start. You should be able to get a lot more vapor.
I build .8 - 1.5 ohm coils when I want to generate a lot of vapor. However, I have to change my juice to increase VG and lower nicotine, otherwise, it's harsh. So, I just mix special juice for different devices. RBA's hit so much harder that I usually use 6 mg/ml to 12 mg/ml max. I get plenty of vapor. Vapor is also largely about air flow. If you do everything right and don't have the air flow, you won't get a lot of vapor. So, I have my sets of micro drills. Careful, measure twice, drill once. Baby steps. Easy to ruin a setup with too much air flow. Also, the lower the ohms, the higher the watts. Often vape over 10 watts, but only on very low ohm coils. My normal vape range is 7.0 watts. Good Luck!