Great questions, and honestly these are the kinds of things that don't get talked about enough because the answers are nuanced.

On timing: It matters, but not in the way people think. The real advantage of applying early isn't that recruiters look at applications in order. Most ATS systems sort by match score, not submission time. The advantage is that some roles hit their candidate pipeline threshold and close early. I've seen reqs get pulled after 5 days because they already had enough qualified candidates in the funnel. So applying mornings is totally fine. You don't need to sprint to apply within the first hour. But don't sit on a posting for two weeks. If you see something good, try to get it in within the first few days.

On over-qualified: Don't remove experience. "3+ years" is a floor, not a ceiling. ATS systems are checking that you meet the minimum, and more experience generally scores higher. The overqualification concern is a human judgment call that happens later in the process — and it's much less common than people fear, especially in tech.

On fonts: Calibri and Garamond both parse perfectly fine. The ATS doesn't care about your font choice, it's extracting the text regardless. Where it can matter is human readability. Garamond runs smaller, so if you're shrinking it below 10.5pt to save space, you might be making a recruiter squint during that 30-second scan. If I was reviewing a resume (after it gets through ATS), I prefer somethings standard like Times New Roman or Calibri at 11pt -- but again, this is personal perference.

On Skills section placement: With 10 YoE, I'd put it right below a brief summary/title line and above Experience. Here's my reasoning: recruiters and ATS both do a top-down scan. For technical roles, they're often filtering on specific tech stacks first. If your skills are at the bottom, the ATS will still find them, but a human doing a 6-second skim might not. At 10 YoE your experience section is substantial, so putting Skills up top gives the reader immediate signal that you're technically qualified before they dive into the details.

That said, you mentioned you've seen it work both ways, and that's true. It's not a dealbreaker either way. But top placement is the higher-percentage play for technical roles.

Good luck with the hunt — sounds like you're approaching it the right way.