I'm a part time lurker who signed up for an account just to share my experience. I recently had the honor (no really, I enjoyed it) of planning a large family trip to WDW. There were 28 of us and I was very nervous about how we would dine as a large group. For most places I split our group into two smaller groups since a lot of places limit how large your party can be. There was only one time where we had to split our group into 3 parties for the ADR selection. A couple of times we would have two reservation groups but they would need to split us up into tables of 6-10 or something like that in order to accommodate us. I can think of only one instance where we weren't seated directly next to each other. Disney did a great job, as you would expect, of seating us all near to each other so it always felt like we were dining together.
We tried to do one TS meal per day as it would have been a lot to coordinate every meal otherwise. Even still, we did a lot of our quick service meals together. I did a TON of research prior to the ADR day and I was able to get exactly what the group wanted following "normal" ADR strategy - book the toughest reservations first.
Going off of my notes on the trip, these were our ADRs for our group of 28:
Hoop Dee Doo - 28 all on one reservation - I believe we were split into three tables next to each other in the theater
Chef Mickeys - 2 ADRs - this was during the renovation so we actually dined in a large ballroom in the Contemporary. They split us into three tables.
San Angel Inn - we had to do 3 ADRs for this one - we had three tables, all next to each other.
Hollywood & Vine - 2 ADRs but this was the one instance where we had to dine apart from each other, I think split into 4-5 tables
Cinderella's Royal Table (ladies breakfast) - 2 groups of 8 if I remember correctly - my wife said that they were able to seat all 16 together!
Kona Cafe (gents breakfast) - one group of 10 (if you're doing the math 2 people had already left at this point bringing our group down to 26)
Teppan Edo - 2 ADRs - I think they had to break us into 3 hibachi groups but we were all next to each other
All in all, it was a great experience. Sure we had to wait a little longer at times to be seated next to each other. For what it's worth our age group started at 10 months and went all the way up to late 80's. Most of us are in our 30's with younger children and thankfully a very easy going group of people.
Judging from your post count you have quite a bit of experience but if I could offer some tips... Don't let the size of the group intimidate you. If it helps to split into smaller groups, split into smaller groups. Definitely get a partner involved in the planning and reservation process. My wife was very helpful in making the reservations as she sat alongside me and would quickly throw a second (or third) group together when needed to secure the necessary ADRs. She was also very nice for listening to me ramble on about my dining reservation strategy as it changed from day to day!
Best of luck with your group reservations, no matter what you'll have a great time at Disney World!