You didn't give us enough info to calculate things for you Triple7. Not trying to give you a hard time my friend, but I think that's because you don't know enough about this stuff yet to know how it works.
Mooch gave you a link to Baditude's blog in post #4. There is also 'One stop reference shop for new and experienced vapers'. Both have really good information and you can pick what to read first. Look for info on Ohm's law for vaping, batteries and how to select the right one for what you want to do with it and how to use mechanical mods safely. It probably sounds like a lot of reading, but it really isn't and once you've done it you'll understand it
In a nutshell, with a mechanical mod like the Nemisis the lower the resistance of your build the more amps you'll draw from the battery. With an 18350 battery you can get to the point of drawing more amps than it can safely put out fairly easily. Do that and the battery will heat up in use. Get the batt too hot and it will vent, which can be seriously painful if things go really wrong.
The resistance you end up with depends on how many wraps of what gauge Kanthal you make on what pin size (the inside diameter of the coil). If you use dual coils the combined resistance of the two will be half of each. That's why folks have suggested you get a ohms checker to know what resistance you've actually built. In the links given you you'll find info on online Ohm's law calculators and coil building calculators like the one at Steam Engine, all of which make this stuff pretty painless to do.
If you just don't have any interest in getting to know how this stuff works and you keep on using mechanical mods, I suggest you keep having your coils made for you. IMO that's less of a risk than to be building your own without sufficient knowledge of what is safe. Or switch to a regulated mod. They have protection built in that will take care of you as long as you have batteries that will handle the amps required and battery specs are given.
