I just ordered a Kayfun mini V3 clone from 3F Vape in China, 15 bucks shipped. You can also get from fasttech but they don't appear to have the SV logo on them and they cost more. I have a KF plus V2 clone (nice MTL but not top fill like the V3 & 5. Also have an SXK KF mini V5 very well made but just a little too airy for my taste, and the reducer inserts you can buy for a tighter fit don't fit it.
Not surprising. I bought the sxk mini for my gf's authentic, to nano-size it and to have a cheap source of spare parts. Except about half the parts don't even fit, on the deck the neg screw won't go all the way down and the positive post wasnt in it, it came in the bag but when I tried to put it in it won't fit at all. Its a good thing all she needed was the upper part, but she won't be able to make an extra kayfun bc the rest of it is a paperweight.
On the other hand I bought the mini sxk taifun gt3 to do the same thing for my authentic taifun gt3, (mini-size it). on that one the quality is 10x better than the kayfun and all the parts fit, but in my personal opinion the taifun gt3 is a much simpler and better designed tank, though my gf would probably disagree with me on that
But it is imo easier for mtl'ing, all you have to do is unscrew the base and slide in the peek inserts, I have one in now and they go from a slightly restricted lung hit to a fully restricted mtl with the AFC open all the way.