I've heard it said that the Pyro doesn't vape as well in single coil mode as dual coil. I tend to disagree, granted the Pyro in single coil will not have the surface area that a dual coil will and the air flow ramps don't match as well in single coil mode. But, you have a massive, wide open deck to work with. Why not take advantage of it to and build a single coil that will utilize the unique air flow design of the Pyro. Of course my first thought was a bigger coil to fill the void. I have been using 3.5 mm dia. coil for some time, so I decided to try a ss 26ga. 4mm coil to start. The 4mm coil looked tiny inside the Pyro. It did vape very well and I was very satisfied with my purchase (since I rarely use dual coil builds). It kept bugging me that I wasn't utilizing the full potential of the Pyro. I decided that if big was good bigger would be better. So, I dug up a 6mm drill bit and wound up a ss 26ga 6mm coil, it turned out to be a monster, but it fit. I'm installing this monster size coil and disaster happens, it slips from my hand I hear it bounce twice and ... I spend far too long searching for it, become frustrated and decide to take a break. While taking a relaxing vape break, after accepting the I wasn't going to find that *** coil, I contemplated what I had learned. 1) the 6mm coil was huge and would put it much closer to the drip tip 2) their wouid be a large amount of wick at the center of the coil that does nothing 3) still not getting the air flow where I want it. My solution was a massive oval shaped coil. I set about measuring every small rectangular item that I could find lying around the house. What I had in mind was something like a popsicle stick, but was coming up empty. While digging through our kitchen junk drawer, my son came in and asked what I was looking for. I told him I needed something like a popsicle stick for a project. He goes I got a stick from a corn dog that I ate, you want that? Eureka, That corndog stick measured to be 7mm x 3mm, it is perfect. After making a ss 22 ga. 7mm x 3mm oval coil I had a bit of trouble removing the wooden stick. After getting it out and wicking this bad boy up, wow. Great flavor. I'm vaping a 4mm round coil and the oval coil both on the Pyro (I have 2) for comparison. Forget that, their is no comparison, the oval coil is out performing the round coil hands down. Ps. Found this on youtube (after I finished of course) He makes a Clapton oval coil, I just used ss 22ga. instead. Same principle. He installs the oval coil on a 2 post deck. In my application the oval is horizontal to the deck instead of vertical as his is.