There is a method. Do a quick search, I remember reading or seeing it and it was well explained.
As I recall you divide the difference in altitudes by 9.3 then add the result to the QNH to get an approximate QFE for the target.
Sorry can't find the link at the moment.
I wouldn't hold your breath with regards to the Hornet. The Harrier will be at least a year in game before you see anything regarding the Hornet. The AG radar seems to be an issue I'm afraid.
For me I went in single player, quick start cold start mission, make all the assignments/changes. Once they are set I go to the free flight quick start mission and test it all out and make any final tweaks.
Only got in once and no aircraft available (of one's I own) so looks good for guys participating. :thumbup:
I'll try a few more times but I'm glad to see the test being well attended, hopefully it will help sort out the issues.