Apply in round 2 with 720-750 or round 3 with 750-780?

Hello, forum. I'm trying to decide if I should rush my GMAT to make the round 2 Harvard deadline or take my time and wait until round 3. Any feedback will be greatly appreciated.

I'm fortunate in that my verbal is in the 99% with no study, but I've never spent much time on math so need a little work (I'm in the 70-80% range). If I blitz the math over the next few weeks and take the test early January, I think I can hit 750 or maybe 760 with the right luck, but my failure case would be 720. If I wait until March, I can most likely study my max up to 780 with a failure case of 750.

Is the score difference worth waiting until round 3? Due to work commitments I didn't think I could start an MBA next year (was going to be out of the country on an expat assignment for a year, but the duration was recently cut to 6 months) so I have a good excuse for applying late...but I'm not sure how the late application will affect my chances.

I feel that my work experience and background is solid, but my biggest fear is that I just turned 30 and might be considered too old for a top tier program. I'm only looking to go to a top 5 school and don't want the window to close on me. Is a worst-case 720 good enough, or do I need the 750+?

Here is my background:

Work Experience: 5 years
Job: Manage a product mktg group at one of the largest tech companies in the world
Undergrad GPA: 3.5 (top 10 undergraduate business program)
Misc: Co-founder of a non-profit that raises tens of thousands of dollars yearly for local high schools
Extensive international experience
Speak multiple languages
Division 1 athlete
Can get letters of recommendation from heavy hitters in the tech industry