If you're going through the process of rebuilding the transmission, I would highly recommend rebuilding/replacing your torque converter. There is no thorough way of cleaning (that I know of) all of the years/miles of sediment out of the torque converter other that cutting (machining) the converter apart. This sediment will more than likely hasten the trashing of your newly-rebuilt transmission (don't ask me how I found this out).
See if you can find a rebuilder that will rebuild YOUR original converter so that you can preserve the originality of your car. Photograph all of the existing markings so that you will be able to reproduce them. What ever you do, don't let them paint the converter (like they usually do).
If you go this route, post the name of the company that rebuilt your unit. I'm going to be traveling this path in the future.
Frank