9 wraps on 2mm bit would give about 1.3 to 1.5 ohms as far as I remember. Been a couple of months since I recoiled, and I usually stick to 1.5mm bits.
As for dual coils, it would be half the resistance.
I would suggest to anyone just starting out to try their hands at a single coil first. Take some time perfecting it to your liking before going into twisted, zippered, tin man,dragon, etc coils. (hype in my opinion, but I'm not one for clouds or flavor)
Secondly, start with a higher gauge wire like 30 or 32. It's softer and a bit more difficult to work with. Why start with it then? Because it would be easier to work with 28awg after you've perfected 30awg or 32awg. Ask those who started coiling with 28awg to work with 32awg and they'll be cussing and swearing cause they're too used to thicker wires.
As for dual coils, it would be half the resistance.
I would suggest to anyone just starting out to try their hands at a single coil first. Take some time perfecting it to your liking before going into twisted, zippered, tin man,dragon, etc coils. (hype in my opinion, but I'm not one for clouds or flavor)
Secondly, start with a higher gauge wire like 30 or 32. It's softer and a bit more difficult to work with. Why start with it then? Because it would be easier to work with 28awg after you've perfected 30awg or 32awg. Ask those who started coiling with 28awg to work with 32awg and they'll be cussing and swearing cause they're too used to thicker wires.