In Legendary there seems to be only one (or two tops) queue at a time active. So if you miss that queue you usually have to wait until this match finishes and the next queue starts. Once you hit that queue and are quick enough to rejoin it after the previous match has finished the next match is popping within seconds.
The drawback with this method is that you are playing with/against the same people all night long.
All in all the average queue time in Legendary fleet in Europe in the evening (7 pm - 12 am) is in the low one-digit area (< 4 min).