I sent mine late January/early February after I found out I didn't match to UTSW and was waitlisted. I've heard similar things from others. I would make it personal and explain why this school is the best place for you to be and what you've been doing since you submitted your applications.
Our weeks really vary. The beginning of last semester was hard because we were juggling Human Structure (anatomy), Microanatomy (histology), and a third class (genetics, biochem, bugs and drugs, immune, etc). We generally had 3 lectures per day (I streamed at 1.6x) and something in the afternoons 2-4x/week. Once we started finishing things up, our schedule lightened and it was easier to manage. Starting in January we will begin organ systems and it will be nice to focus on just one thing.
We have TBLs ~2X/month. They are a waste of time in my opinion. I don't know why they make such a big deal about it to applicants. I would not use this as a factor when choosing between schools.
Overall, UTSW is TOUGH. The curriculum was hard before and it is even more accelerated now....my saving grace is that we are P/F. I know I wouldn't be happy if it was any other way. While I have been challenged, I have still been able to pass everything and maintain a social life, exercise, spend time with my boyfriend, and go out once a week. Others have more or less free time depending on the person.
...Just be warned that if you come here you will be working very hard from day 1 🙂 Probably true at any school, but especially here!!