slimming queen; how fast and how long before swarm?

[windfall]

I see frequent reference to the hive slimming down the queen prior to swarming to improve her flight.

How fast does this happen? How long prior to swarming is it noticeable?

The 3 deep frame Ob hive I am keeping made and mated a queen a few weeks ago. She rapidly filled all available space to lay and for the last days has been ambling around looking for the stray empty here and there to fill in, as well as expand outward slowly as they move and consume their stores. The first new round of capped brood should begin hatching out in the next 3-4 days making some space to lay (but crowding the hive even more).

I would swear over the last 2-3 days she has thinned down noticeably, and the hive is pretty packed at this point;but they have not begun any new queen cells.

Is the slimming a consistent predictor to swarm or does it also occur if she just slows down her laying?

I am planning to pull a frame out, but was going to wait a few more days and put together some summer nucs at the same time. Dare I wait?
If they are slimming her for swarm prep, how committed are they at that point? Am I better off pulling her as well and forcing them to start again?

[Kathyp]

do you see any swarm cells? 

[windfall]

no, nothing started as of yet.

But I have been down that road in the full hives before, and I know they are committed at that point!
Since I have never gotten to watch and observe so regularly, I doubt I would have noticed the change in queen size in those cases. So it has me wondering if this is an early sign to be noted, or just the ebb and flow of hive cycles