Got my SXmini M Class Yesterday, I dont have the Vengeance RDA yet, but I do have a Magma V2 which is nearly identical but the posts are closer together on the Magma V2 vs the Vengeance.
I could only fit 2 coils on it with the 3mm white ceramic rods. The Rods touch the deck and the coils are 8 spaced turns of 30g pure nickel wire. The M class reads it at 0.110ohms.
So im sure there is still much tweaking and playing with coils and stuff left to do before I give it my final verdict but so far its a very nice unit. My last unit was a Joyetech Evic Supreme 30w. I liked it and its nice LCD screen, but it had a problem where it wouldnt always fire the coil so I had to press the button many times.
On temp control the unit works as it should, Joules is confusing, People say to treat it like watts on other forums, I havent played with this much yet, I started at 20 but it didnt heat up enough.. Im at 50 joules right now and 230degree C.
Problem with temp control on here is that it makes it hard to "prime" the rods as it stops firing when it detects a dry coil. Also, I have to keep the air flow open to help keep the coil cool while I hit it. Means I have to hit it hard, still much more experimenting to find the best setup, so many variables to control now!
I prime about .3g of shatter in regular watt mode then switch to joules mode add my hit to the top of the rods (bb sized) and hit it. I usually get 2-3 hits from that and the taste is amazing! I also feel more comfortable knowing my coil is never getting much above 230degrees and no where near red hot like my last unit which I could get the whole ceramic rod red hot with.
When the Vengeance shows up i'm going to build a dual horizontal coil to expose more of the coil to the shatter.