Beast Gauge Cost: Numbers

[Poison_Rose]

So, something tankstuff said got me curious. Namely, this:

if im on war and have to swap i lose half my gauge, or dumping gauge messes heavily with your berserk ir timings, etc.

I'm under the impression that you generally shouldn't use Berserk / IR outside of having 100 gauge. Perhaps I'm wrong about that? If dumping gauge or swapping stances messes with your timings enough that you have to delay IR / Berserk, is there a rough idea out there of how much of a cost that has?

It seems like it would have an effect beyond the "Less than 408" calculated, especially if it happens multiple times over the course of an encounter.