Hi Tom,
If the file is too large to upload you can select to save just the one buffer of interest. You will then get an idea of the file size indicated below.
In the image above we can see that when saving all we have a file size of 12MB. If saving just the current buffer the file size is reduced to 4MB. If in any doubt you could always upload your file to the waveform library where once all the information is filled out, can be opened by anyone anywhere in the world.
Hope this helps.
Kind regards
Ben