Well the full conversion ran last night for the other team.
- The current four Visual Source Safe repositories had a combined size of 11.2 GB
- The wanted code tree was 490 MB (mix of text and binary files)
- The subversion history dump of the above code was 4.1 GB
- The subversion repository size is 620 MB
- The copy/dump/load took 12 hours to run
To merge the repositories together, I had to run a few svn commands between svnadmin loads to create/move/delete so the sub-trees were all happy.
One oddity noticed was that some files were different between the old and new repositories. This was due to the file being altered by a developer is the US in his time zone, and then within the time-zone difference, a developer in NZ changing the files also. So even though the US change was made first, the dump program sees the NZ one having the earliest time, thus swapped the order of these edits. (Because VSS is done on local time, and the local client alter the repository, so different time-zone really should not work on the same repository)
But this will not happen now, because subversion itself does not have this problem.