Sorry, but 'rotsa ruck'.
Just when you think you have the route all worked out, one of the 15 countries airspace you'll be flying thru will re-route you on short notice. You might even be lucky enough to have this happen on the ground, haha.
I think what might be money well spent would be a call to one of the many international flight planning organizations and have them run some flight plans for your route and equiptment. They will at least be real world expectations.
Good luck!