I guess it depends on the maps - any idea what Garmin map size will be required for the whole route? Shit, I've only got Europe I think, probably doesn't include Turkey, etc. so I'll need to buy that as well. So maybe 16gb of maps at the most? Hmm..
DK - not downloaded them yet.
I'll just get the free OSM ones and download a strip covering where I'm going, not the whole countries. I don't expect them to be too massive.
I bought a couple of 32gb cards the other day. I think I saw 64s but didn't think I'd need them.