Thanks for all the replies.
So INPA is some sort of diagnostic tool, which I don't have. Maybe I'll try using a kitchen liquid thermometer, and bending it to reach the fluid through the fill hole.
And as far as shifting through the gears, it sounds like all I need to do is put it in manual mode, and while at idle, shift into each gear, and let it kick back down. When I did it during the drain & fill, I rev'd the engine enough to allow it to hold each gear, even 4th and 5th, without kicking down, allowing me to control which gear it was in. I didn't catch the 30C - 50C temperature target, so I'm sure I got the trans fluid way too hot.
OK, I'll report back how much, if any, fluid I have to add.