Need some advice here. I was always a wide open air rta/rda user for the entire time I vaped. Then I bought a restricted lung pod device for use at work that I ended up using to quit vaping for a short time. Long story short, I bought a Billet Box to put on a shelf with my vape collection......curiosity got the best of me and now I'm vaping again. Between the restricted lung pod and the BB rba's I've done a 180 and decided that I like .7 - .9 builds at 18 - 22 watts much more than I ever enjoyed my standard .15 builds with a lot of power. I want a Kayfun, I've ruled out the 2019 Lite. I am interested in the 5squared but am unsure if it's too airy? Can anyone tell me if the original 5 or the 5squared are restricted lung rta's? I know there's af control, but more concerned about chimney diameter. I don't want to buy one that's pure mtl, but am looking for a restricted to very restricted lung. How is the Prime, is it a true mtl or should I consider that? Thanks in advance to anyone that replies, for the money they cost, I just want to be educated before buying.