CharlesB's answer in the linked question will get you started. svn2git creates a git repository that has branches linked to the appropriate SVN branches (it is possible to set up a SVN repository where this doesn't work, but assuming the SVN setup isn't terrible, it will work)
You merge your initial git repository into the git repository created by svn2git, and tell your git developers to use that repository (or a mirror of that) from now on.
Then you periodically use git svn to move changes to/from svn from your git repository.
git svn fetch will pull changes from an SVN branch into a branch in your git repository.
git svn dcommit will move changes from a git branch into SVN.
To your git users, the SVN repository will appear as the remote origin. To your SVN users, your git users will look like they are using SVN directly.
There is some overhead; it's not set and forget. New "public" branches can only be created in SVN, and you'll need to get quite familiar with the options of git svn.