My own experience with VGML J meals is that it's unusual for them to show up as ordered (mind you, I haven't flown in J on AC in over a year so perhaps things have changed). I have had much better luck with DL and UA. The past year and a bit we've flown BA and AC in PE (WT+ on BA) and BA had no trouble getting us the right meals, AC missed me on one flight but my wife got one, and we both got one on another.
The best advice is to be prepared to not get your meal to avoid disappointment.