Does one still need to offset 15nm before descending in case of an emergency.
- no. See Mutt's post 4. Your nav chart should have relevant existing nat tracks marked on it so that you descend as appropriate. As Mutt says, you need to finish up offset from
existing tracks.
Re Q2: I believe it is company requested but I have had them 'modified' by ATC. There cannot really be a "system of Random Tracks", although there are inevitably 'favourite' routes that will cross the Nat Tracks.