Using the technique in my how-to on about 5 4L30E trannies so far has yielded an average of 8 quarts. You get about a quart from dropping the adapter pan and there's the additional fluid that comes out when you start cycling through the gears once you get to that stage.
As Spazz is getting at, it's better to have it and not need then need it and not have it.![]()