I am using an Ipv4s with .15 ohm ti dual coil in a rda. 475F at 55 joules. So… my question is…How many "watts" out of the 120w am I actually using? I like the Ipv4s, however it seems a little large and I am considering a single 18650 tc mod but would like to know if it would be able to "keep up" with the ipv4s as I am using it now. Many thanks for any input, Jim