Just given this a go myself as I had some time on my hands. Downloaded the full Europe map as that seemed a better match for what I had - looking at the original case from when I got my car almost four years ago, it lists most countries in Europe, but is labelled Europe 1 (V4). It just about squeezed onto the original 16GB card,
The process seemed quite straightforward thanks to the instructions on this thread, it's just time consuming as the download took the better part of an hour, although that gave me ample time to copy and remove files from the SD card. I did try opening the OVERALL.NDS file, but couldn't make sense of it.
Getting the files onto the card took around 45 minutes, although early on it was quoting over ten hours due to starting with lots of small files, While I know the system is shared between VW, Skoda and SEAT, it was slightly surprising to watch folders for each going onto the card given the card and packaging are branded SEAT.
I went from 0730 to 1310 but if I'd taken the basic Europe 1 option I'd have gone to 1410 - perhaps 1410 with the full maps would have gone over the capacity of the card. Most of the time I drive roads I know, and often use Android Auto when I don't, so for me this is more about when I trade in the car, having a recent update will look better than having the original version.