I don't fully understand why everyone gets upset over browser leaks when in private mode - most websites interested in tracking private sessions will just associate private and non-private sessions by IP address.
If you're paranoid enough to use a VPN for 'private' traffic, you should probably be running such sessions in a VM using something like the tails live CD.
If you're paranoid enough to use a VPN for 'private' traffic, you should probably be running such sessions in a VM using something like the tails live CD.