What ballpark range do you need to be to take Shadow Empress down

I always use Elite Puppet and Phoenix to check when DR ends because of this. You end up with the same problem in reverse since there's a delay before the icon appears as well.

When I used to use a timing of 60 sec cd after I saw DR ended I always ended up randomly being killed by a DR because I was too late in stopping. DR duration fluctuates, it can sometimes be less than 20 secs and sometimes be more than 20 secs due to the server lag time I would believe. Factors like DoT and venom would make this timing even worse and sometimes even extend her icon for some reason. However, her real CD time will almost never change. Using a 80 sec CD time guarantees that the next time she will be ready to cast DR again you will be ready. I'm not going to keep trying to add or subtract extra time just to make sure I'm alive. 80 seconds would include her DR duration + the next time DR would come again, much easier to measure than 65.