It is somewhat floating. It isn't flush against the body. But you can pull up, only a half note tops. I own a Wilkinson VS100, and it keeps the guitar in tune very well. I can do flutters, but only
very subtle ones, or the guitar will go out of tune.
One could lubricate the nut. That might help. Or insert a
locking nut. That would keep the guitar in tune, after less subtle flutters.
You should look through the Gotoh site. There are a
lot of options. There are even a couple of them which look like the one on
John Petrucci's guitars.
http://www.hosco.co.jp/HOSCO_ENGLISH/Pages/Gotoh.html
Kind regards,
Myst