New
#21
You'll need the latest MCT. Each MCT is tied to make the version it was released for - the exception to this rule is the 1703 MCT which if you run it now says there's a newer MCT available and will download it for you.
I make the USB rather than an ISO, but the 64-bit USB is 3.58GB, so the ISO should be about the same. As I recall, it was 1703's ISO that needed a dual-layer DVD - looks like MS have been careful to reduce the size again for 1709.