If there are differences between time passing in one shadow and time passing in another, and there are an infinite number of possibilities in shadow, then a person who can direct their course through shadow can attempt to find a slow-time shadow. In other words, they can move themselves to a shadow wherein 1000 years might pass for every one second in Amber or something ridiculous like that.
Well, I usually call these shadow dilations “fast-time shadows”.
And there are definite recommendations I would make to keep Players from the temptation of genre-busting.
Time flow in the universe is an opportunity to provide a Player with more choices. Certainly those choices have narrative consequences.
1. Time at the reality poles is more significant than elsewhere. One result of this is that going off to fast-shadows to gather armies often means you have to spend more time training them to compete with an army gathered closer to Amber.
2. Time at the reality poles is more predictable. One result of this is that fast-shadows can “fall off the clock” and/or become unstable. Control of shadow is never absolute, and certainly not absolute when you are not present.
3. Because Trump has time-dilation and narrative powers, I limit stable time-flow to 10x. There is a tidal shift of time depending on topography, but on average Amber is 1x and Chaos is 10x.
4. Associated with the last point: Trump contact between shadows in excess of 10x is problematic at best. Stepping through extreme time dilations is dangerous.
5. IMC normal max time-flow is 20x and this represents a very unstable shadow. The whole place might be gone when you come back after an absence.
6. Average results in seeking “fast-time” shadows is around 3x to 5x. You have to practice a lot (or go south of Ygg to Chaos reflections) to approach 10x shadows. Note that finding deliberate intangible qualities by shadow walking is always very difficult. Advanced Pattern is useful for this.
7. Since distance can be a significant factor in my Trump rulings, this is another choice/threshold to consider. Many Trump Artists cannot reach Chaos-side locations and place Trumps are seldom stronger than person Trumps.
So if simple spells with 30 minute hang times for each of ten spells in a rack are the easiest example — you could have a Sorceror with Trump and his own fast-shadow really be out of Amber something like:
30min x 10 spells = 300 min / 5x time = 60 mins in Amber.
Complex spells that take hours to hang are still hard to do quickly. I find this works pretty well in most narratives and also provides dramatic choices for PCs.
Basically, I advise PCs to try and remember that infinite choices doesn’t mean infinite wise choices or even infinite control of those environs.