I have an overflow tray for a hot water heater which is about 1m wide that I slide under the car to catch the splash when I inevitably drop the oil filter into the drain pan.

I did an oil change on my auto box a couple of months ago. The highly detailed and very precise instructions did have me a bit worried until I found the video (link below) which was done by a big LR aftermarket supplier in the States. They dilute the procedure to the basics and it is very simple. I did make sure to follow the proper procedure to check the fluid level afterward though, and everything turned out fine.
http://www.roverparts.com/resources/videos/transmission-service-freelander/

Yes it's the way I would do it and also I'd measure what came out and put back the same amount.