How experienced are you making & wicking coils?
If you're relatively new, why not just build simple coils initially. I've been vaping for over 3 years, rebuilding for over a year, and I've not found any advantage for using exotic coils other than for pure entertainment or enjoyment value. I build simple microcoils (dual coil, 0.6 ohm 28 gauge Kanthal) in my Patriot RDA.
If using organic cotton as wick material, you may be experiencing that "new cotton" taste which can taste burnt innitially. After a few hours vaping that taste seems to disappear.
If there happens to be a short or hot spot in your coils, that can cause a burnt or metallic taste. Did all of your coils glow evenly, from center outward?