I'm still on my first build in the Drop. I went for duals but I think adult beverages were involved. Ended up as a single coil at 3.5mm by the looks of it, using 28g SS, came to .9ohms. Hits great at 14- 15W with 3 tiny airholes open.
It is getting a bit gunky and will get changed soon. All this to say Go For It with a single.
I did get the coil to peek over the posts by 1/4 of the diameter. I went in from the top and folded the coil in between. I'm sure this build is not Pro vaper approved but it seemed like an OK way to start on this RDA, with lots of room for improvement.
HTH