I aim for 203, just like you did. A few thoughts, although I'm not one of the most knowlegable here:
- The grade of meat will make a difference. Higher grade, better results.
- How you trim is important in keeping that juiciness level. Don't overtrim
- Use your fat trimmings to make beef tallow (slow cook it in a crock pot). You can use that to baste your brisket, and help keep it moist.
- I don't leave mine on the counter when done. I wrap in foil, then put in towels/blankets in a cooler to rest for a few hours.