I switched to titanium and have better luck. It just seems more durable and I don't get the fluctuating resistance like I did with Nickel.
Grade 1 CP Titanium wire is what you are looking for and a lot of jewelry sites carry it because it's hypoallergenic (I think).
I read as many posts as I could find by a member named Rossum who started using it before most of us. I also bothered him directly to pick his brain and his posts have some great information.
I use twisted 30ga mostly and believe I may have a line on some 28ga but won't know until next week. A twisted 30ga spaced coil on an 8/32 screw puts me at .31ohms which I can vape at 340 degrees until the
tank runs bone dry without a dry hit (ymmv). No problems so far getting a solid contact with my posts and very little tweaking once it's set up. It's been a real good vape! You'll pay more for it but to me it's worth it.
I washed mine with hot water pulling it through a scotch bite course pad and it produces great flavor.