Hey NeanderthalMan! Welcome to GMAT Club.
A bunch of not-quite-rights in your post that we wanted to comment on.
NeanderthalMan wrote:
I know I need to score in the 98th or 99th percentile
Not true; people get into Wharton all the time with a total score in the 85th percentile or above. Average GMAT for accepted students at Wharton is currently 725 - yes that's high but it's 95th percentile(ish) and remember that it's an average, there's plenty of people with lower scores. Having both quant and verbal each > 80th percentile is recommended. The schools are flexible, they look at the whole package.
NeanderthalMan wrote:
I must use the essays to discuss how my previous academic trajectory differentiates me.
Not true; there's nowhere in your essays where you could discuss this, and anyway, they see straightaway from your app what your academic background is. Instead of discussing how that "differentiates you", you should focus on the specific essay questions and talk about why an MBA is the right next step (the angle of "how I'm prepared, given this specific background" is always helpful for everyone and will be especially so for you).
NeanderthalMan wrote:
Unlike the majority of GMAT test takers, verbal has historically been my strong suit.
Lots of people applying to bschool are better on the verbal side; this is true for probably half the applicants we see.
You definitely have an interesting background and the schools are often very open to those coming from a different path into bschool - but there's also challenges as a nontraditional applicant, in terms of showing how the MBA is the right next step. Lots of resources here at GMAT Club so you're in good company with everyone else applying! Good luck to you on the test and everything else!
EssaySnark