I think the size and event agenda dictate a lot of the ratio.
My daughter’s wedding at a private farm / weekend estate last summer had just under 100 guests - half from out of town - with two togs and no professional video. Her Proof CD had 3,200 captures from the out-of-town guests welcome reception at the hotel, Rehearsal Dinner at a Club, Dressing and (small) Wedding Party set shots, the Ceremony and the outdoor Reception, tented Dinner and (DJ) Dancing. The set shots captured all the traditional themes and combinations and were less than 10% of total. The guests were bused out to the farm from a meeting / parking location in the city and there were shots getting on and off the Coach. Her photographers did a great job getting all the guests in candids in small discussion groups during the cocktail reception and moving to the dinner tent. Her ‘event manager’ / good friend (great idea, BTW), who trailed the Second Shooter, used a checklist to ensure everyone was in at least one set of shots. The First Shooter concentrated more on capturing guests and Party, and Ceremony within the scenic landscape and residence. Half the candids had family or Wedding Party in them.
I think that worked because the event was small.
In contrast, we attended two weeks later a ‘New York Wedding’ at
Oheka Castle on Long Island. Six still togs, 2 videographers, 2 drones, 20 tables of 12 plus the wedding party of 20 at a head table. During the 90 minute cocktail reception the togs actually asked our names and made a brief recording in the camera of the last names in each candid group. They did a ‘Pause and Pose’ with each person / couple as we left the receiving line. That was crazy efficient if the goal is get a shot of everyone, but the Receiving Line took nearly an hour. Two live bands (so no breaks), and they actually had a camera on a boom.
My best guess is 15,000 clicks at that event and <10% were formal set shots, but in my daughter’s the Couple was in a
much higher percentage of the candids because the Bride and Groom can only be in one place at a time.