I use CottonMan Mavaton Select and Carolina Blend corded cottons.
That's a 120 gram bag of Mavaton cotton along with a mod/RBA for reference.
I cut the corded cotton to about 65mm strips. Then strip off what I need for a 3mm coil.
Twist one end of the cotton and thread it through the coil. This is a 3mm ID Clapton coil on a Dvarw DL RTA deck.
I work both ends through the coil for even shoulders. Then trim and place the cotton as need be.
It's pretty straight-forward, really. And, wicking is not tedious whatsoever (IMO). The more one does it, as with any learned skill, the easier it becomes.
as to wicking...........
Wicking any RBA is a total "feel" thing. Once one knows the "feel" of a good fitting wick in a coil one can reproduce that every single time.
Rule of Thumb with Wicking: Too little = gurgling/flooding. Too much = dry hits/muted flavor.
Ideally one wants a cotton wick to be tight fitting within a coil when moving the wick side-to-side, but not so tight that it moves the coil when one moves the wick side-to-side. If using thin wire, one might have to hold the coil in place or reposition the coil after threading.
A wick should move side-to-side within a coil while feeling some friction/resistance.
And absolutely, not loose fitting within a coil.
Again, wicking is a total "feel" thing.
If using rayon for wicking, one needs to use ~30% more density versus cotton. That's because rayon contracts (cotton expands). As noted in both rayon threads, one wants a rayon wick to fit fairly tightly within a coil (not too tight). You should hear some squeaking as you pull rayon through a coil.
I switch off between using cotton and rayon in all my RBA's.