With 700 hrs you're ready to get the heck out of there? How do you think Captains with 5,000, or 8,000 hrs, feel? And they know a heck of a lot more about flying, the industry, and leadership than you do. I'd recommend relaxing and learning to be better at the job. That will be the bedrock that you can use to improve your resume that might lead to an earlier than expected opportunity at a major airline.

You can apply at any time. After a break of x weeks/months you're no longer an active candidate.

DL said the lowest time guy they hired in 2016 had 2,050 hrs. So it doesn't hurt to start applying now. Keep in mind the average civilian guy had 6,937 hrs. You are years away from that. And at AA the under 30 new hires was 1.4% of the last 500. Youngest 5% was 33 and younger. Consider that the typical guy has 5500-7000 hrs, a couple of type ratings, is a 121 CA, and your odds of getting hired are very low. Improve your resume through steady development and experience and the process of making yourself better will make you more competitive.