Silly question. If you haven't taken the test, score as high as you can, no matter the speciality. Studying isn't just for getting into a top residency after all. If you have taken it, you're stuck with the score.
As a DO your chances at USC are LOW (they've taken about 3 EVER), cook is better, dunno Emory, harbor has taken 1 EVER, highland 1 EVER, getting the picture? Advocate Christ I think has one right now that scored top 1%, but that's a program that literally enjoys displaying their scores on their website.
Fact is, if you want to go to the program, apply. It's a tiny cost with potentially huge reward. If you want to go to a top program as a DO you need to rotate there. I've rotated at a few top tier programs now, the residents that are DOs without fail have also rotated there as fourth years. And, as someone else said, there's much much more to your app than a score. The score is just something to get your app not screened out into the instant reject list.
This whole thing at times feels very random. I do not have top tier scores. If I was an MD I'd have probably just barely upper 1/3 scores (gpa and boards), but do have two SLOEs with honors from well known places. I applied BROADLY (70+), and have 14 invites, mostly to mid tier and a few upper tier programs, and my classmates, some with higher scores, are having some difficulty. I attribute this to my SLOEs and lots of apps. Good luck as a DO for top tier places, you'll need it in addition to hard work.