I was mainly having fun, since would not expect that version to have more flash. My guess is about 1GB more will be available, since will not have Wiz and carrier bloat, but will still have all the sensor related and other bling-like software, since part of the device design. Total free will probably be a tad over 10GB.
1gb more is better than 1gb less (some have only 8gb). That in itself is a 2gb swing.