I suggest that you do not drain the torque converter until you feel comfortable to do so. Removing the pan and filter under the car is already a hard work. To make up for not draining the torque converter, you may drain the pan every 5000 miles by the drain plug (easy work); change the filter (hard and massy job) every 15000 to 25000 miles.
Whatever you want to do, you need to have a new washer for the drain plug. It will be better if you can have a spare drain plug handy too. You may sripe the hex head of the drain plug during removal. If you reuse a striped plug, you may have hardtime unscrewing it next time.
I use Topsider to suck up the tranny fuild about every motor oil change, changing about 3 qt each time, not a lot, but that keeps the tranny clean and chemically updated.