If something is really complex / important / hard to change later, then I'll usually stop after the research phase and allow my unconscious mind to chew away on the solution, most commonly for me the 'Aha moment' comes during my morning workout. When I'm really stuck I re-read all my collected material, search for prior art again and repeat the process. Sometimes time forces me to just start building, although those are the times when I typically end up refactoring later.
I definitely agree that time away from the problem to reflect leads to a better solution, but IMHO you have to have a really great problem statement and good context for the subconscious to do its best work.
What I wonder, based on your comment, is if I can distill exactly what I'm trying to do down to a simple statement or phrase, can I use some sort of technique to "imprint" the thought to my subconscious so it knows to go "work on this" for a while. Mind you, this may not even be a thing and this concept is all pseudo-science placebo, but it at least anecdotally rings true for me.