RE: 14MZ Copy Function
Unless I've missed something you are right- the 14MZ does not copy directly to another model. Instead, like you said, it makes a copy of the selected model to either the card or Tx memory and then you rename the copy. Maybe there is some other magical way but that's the only way I've found to do it. Sort of goes like this- I have plane #1 and plane #2 on my card and now have setup a new plane 3 on the system. If I want to copy these new setting to plane #1 then I select and copy plane #3 and save it to my card. If I want these new settings to be known as plane 1, then I usually rename the old plane#1 to .e.g. plane1_old and then rename the plane#3 to plane#1. Really dumb to have to do it this way but it works. By renaming the original plane#1, then you have a backup in case something has gone wrong. Of course, if you don't want the backup then you could simply delete the original plane#1 settings and then rename the #3 to #1. Myself, I like to keep a backup until I've actually tested the settings.
Thinking of... I wonder if Futaba has changed this in the 18MZ? Probably not. BTW, for real backups, copy the card contents to your PC.
Hope this helps.