I was hoping for some guidance in regard to the optional essay from anyone with insight into the admissions process. Here's the background info:

I attended UT-Austin twelve years ago and was eventually academically suspended from the Mechanical Engineering program due to a 1.5x GPA. This is the obvious black eye that I need to address. The truth is that I developed a substance abuse problem (alcoholism) during my freshman year and my grades landslide over the next 2.5 years before my suspension.

After a very rough several follow-on years, I got help and got sober six years ago. Since then I returned to school through a lousy online university and graduated with a business degree and a 3.4 GPA. I enlisted in the Marine Corps where I was meritoriously promoted three consecutive times. I currently work for a Top 10 company in the Fortune 500, where I supervise 20 managers and ~330 technicians. My GMAT is a 720.

I will be applying to UT's evening MBA, Carnegie Mellon's online MBA, and two fallback schools in San Antonio where I live. I know the acceptance rates are much higher in the alternative programs rather than the flagship full-time programs, and I'm hoping that helps my chances.

Here is my question:
Do I answer the optional essay with candor and outline what really happened, or do I go with the standard "squandered opportunity/won't happen again" essay?

On a side note, if anyone would like to weigh in on my chances at either of these programs the feedback would be much appreciated!

Thanks!