There's a middle ground between that and applying to "hundreds of jobs in under two minutes". What I do, what I assume most people do, is spend an hour hand-cr

There's a middle ground between that and applying to "hundreds of jobs in under two minutes". What I do, what I assume most people do, is spend an hour hand-crafting the perfect response for the first application, and then use that as a template and spend five minutes tweaking it for each subsequent one. Anything more than that would be better spent on things that improve your chances for every job you apply for (improving your resume, adding to your github, taking a course, etc).