How long does it take to promote builds from Fast to Slow to Preview Rings?

[Windows Central Question]

I'm currently in the Release Preview Ring but really need a bug fix which has just been released into the Fast Ring. I don't really want to step down into the Fast Ring because of all the other bugs there, but if it's gonna take too long to get this specific bug fix promoted, I might have to. How long (on average) does it take for a build to be promoted from the Fast Ring to the Slow Ring, and then from the Slow Ring to the Release Preview Ring?

 

[xandros9]

Unless this bug is usage-threatening, I would still hold off or temporarily switch to another platform without that bug.

Windows 10 Mobile has "branches," which are basically major versions.

Upon release, it was Threshold 2 (10586), and right now the current major version is the Anniversary Update. (14something something)

Once it goes live, Fast Ring work begins on the next iteration, which is the so-called Creator's Update or Redstone 2.
BUT, work doesn't stop on the previous versions. There are security and bugfix updates that are released for previous versions. The Release Preview ring gets these minor updates first.

Fast Ring builds are promoted to Slow Ring however frequently BUT Release Preview will never see anything that has to do with the next version unless the public release is imminent.

I had to type this quickly and I hope it makes sense.