I use .25, if you wind round a 2.5mm precision screwdriver about 7 or 8 turns will work nicely, even 5 turns will be ok, just remember to squeeze and flame or pulse then pinch as the coil fades (squeeze and flame works best) and don't be tempted to use a whole cotton wool ball, all you need is a piece the size of your little finger before you squeeze it - pleated wool / rolled wool works best, squeeze it gently into shape then roll one end to a point and trim off the wispy bit, slowly pull through the coil until it becomes tight then trim to fit, use a little less if doing something like the Kayfun as you need unsquished cotton both sides of the coil on those...
@Doofry I use 0.20mm kanthal for my micro-coils, same as the guys above ^
How I micro-coil:
Cut 9cm 0.20mm, flame the full length then wind onto a M2 screw leaving 2.5cm legs (coil will be 1.6ohm approx)
Or using a 2mm jewellers screwdriver
Hold the screw end and flame again
Screw out the M2 from the wire, then hold in tweezers and flame again
Luckily I do already have my Helping Hands, makes the whole job easier