I have the Delrin DT from Cherry Vapes. It NEVER gets hot and it does allow more airflow since its a widebore. If you want to go balls to the wall with it, then check out Chain Gang Creations or Atomized Inc on Facebook. They still really wide DTs that fit on Tobhs, Patriots, Stallaires, etc. they have them for the 22.5mm setup and the 28mm setup. So basically for the 18650 and 26650. I got one for my patriot but I had to get a conversion tube because it only fits the halo patriot. but it fits in my stillaire without an issue. I also modified my Tobh clear cap so that I can use the same DT but flipped upside down.
BTW..delivery from Cherry Vapes was fast! I highly recommend them.