When should you rush? Hardly ever. The idea that more should be done in less time is almost always a cognitive distortion of some kind. Things take the amount of time they are supposed to take. You shouldn't unnecessarily dilate either. Think of frying an egg slow or fast. Usually, it depends on how well done you want the egg to be, not on how much time you have to cook. You cannot cram 8 hours of sleep into five, either, or meditate for 4 minutes with the benefit of 25.
Rushing means something has gone wrong before, or the conditions are not correct for your work.
Make a list of things that you need to do faster. Here, for example, I would put running a 5k. But the important things about a 5k is not whether I run it in 29 or 34 minutes, but that I run it at all. Playing fast on the piano might be important for me, but mostly because I need to play well slowly. If I can play faster, then my slow & medium playing will sound unhurried, and thus better.
(Make a list of things that are taking the proper amount of time. These you need not worry about.)
Make a list of things that you need to do slower. That might be a longer list. I have particular trouble with this. I get impatient with small things, and used to habitually undercook my food.
The idea of setting a timer to do research is one example. The idea is to devote some small, discrete portion of time to scholarly writing. Yet the problem is that this leads to unproductive rushing. Mostly, I set a timer to meditate (and thus have a fixed time for my unhurried practice) or to play piano, so that I don't play piano all day long when I'm not teaching. What's better is to schedule a block of unhurried time for writing.