Fucking Kayfun is being a cunting wanker this evening 
It's a lovely vape but has a major design flaw - you can't get at the coil unless the tank is empty*. It's also really hard to see how full it is because even if you use the clear tank section, the top and bottom are stainless steel and they're quite deep.
So I've just spent days trying to get it conveniently empty at a time when I can dry burn it and change the wick. Finally managed it this afternoon. Dry burned, new wick, filled it up, lovely!
Went out with it in my bag and forgot to lock the up and down buttons on my eleaf (OK this bit was user error), got home, took a massive hoover-drag and got a lungful of burnt cotton wool 
I don't know how much it had turned itself up but it was rather a lot - I have the 50W one. It's the worst dry hit I have ever had.
So I now have a full kayfun with a horribly burnt wick and need to work out how to get into it without sloshing eliquid everywhere. Grr.
McNo the actual making coils bit is not difficult. It's a bit fiddly and you need good eyesight but once you get the knack it's no harder than rolling a fag 
I wrote a post ages ago about how to do it but it's a bit outdated now. I should update it when I get time.
If you are getting on well with the subtank you might want to get the next size up - the subtank mini. This comes with a building deck but also takes the same coils as the subtank nano, so best of both worlds if you get on with that style of vaping. The Kayfun has much tighter airflow and is designed for mouth-to-lung inhaling. You might find it a bit frustrating.
I've just learnt about for the Kayfun that allows you to fill it without a screwdriver and get at the coil even if it's full. It's eight fucking quid* from Cloud9 or £2 from fasttech. I don't think I can wait for FT, I think I'm going to suck up the £8. For a bit of metal to deal with a basic design flaw. Harrumph!