As you said yourself in the original post, the 32Mbyte limit is for the text
part of the document, excluding the graphics. Understand that I've never
tried to see whether that limit is strictly enforced, or what happens when
you try to exceed it.
To minimize document file size, don't embed graphics in the documents but
link them instead.
The time it takes to open large documents has very little to do with any
physical limits on file size. It's related to your network bandwidth, and
the CPU speed and available memory on your workstations. It also helps to
have the latest printer driver and video driver for your equipment, as Word
pushes these components very hard.