I found the A7 to be a single coil atty, and i'd recommend 2 things:
that you make a 'Z' coil which is really what it sounds like and pass it over the centre air hole. Nice long tails.
That you make sure you screw the bottom firing pin up as far as it will go. A7's - and i have a couple still myself were well-known for a dodgy positive pin - it would wobble - and short to the threads where it screws into your Reo.
Another solution i used was to get a small o-ring around the A7 centre pin.
Air flow:
problematic - and because it's made from SS - it's hard to drill. It's possible, but an RM2 can be drilled out with a nail file! Because it is chrome coated brass, so you see where this is going..
In any case: they are both single coil atties and to cloud chase you'll have to buy something else
Neither are new atties, there may be better out there depending on how you like to vape.
T