Finishing on a Coticule

[Frankenstein]

Just wanted to ask a couple of questions to the guys who have a bunch of stones, know how to use them, and sometimes choose to finish on a coticule.
What progression do you use before the coti, i.e., natural, one stone, synthetic?
If synthetic or other natural how many strokes/minutes do you end up doing/spending on your last stone (which should be a coti)?
And do you do this for all your razors or just a few, and if just a few, what type of razors are they?

Cheers,

Lindsay