Seconding a lot of what's been said.
My wife, Jennifer Horrocks, and I hosted 2 regional organizers retreats 
back in '17 & '18 and have our next this upcoming weekend. This came up 
in the two pre-covid retreats with some form of dance angels the most 
common mechanism used to integrate the new dancers. (informal 
ambassadors or formal special name tags varied). I agree that 60% new 
dancers is difficult; that's a higher % of beginners than what most 
dances deal with.
My reason to chime in is to flag the *variation in demographics* for 
both your experienced and inexperienced dancers affects the dance.
This upcoming Saturday ContraForce will play at Sautee's dance in N 
Georgia (in the middle of nowhere) in a very old gym. Many of our 
retreat folks will take that evening off to attend. It is a dance at 
which it's not uncommon for 20+% to be new dancers. The most successful 
callers (in my opinion) have, after the lesson, started off with easy 
but not trivial contras and steadily built up from there which takes 
advantage of the experienced dancers knowledge and doesn't bore the 
experienced dancers to death.. 20% is not 60%. Mentioning because there 
are always beginners at that dance and not all callers handle them well.
I believe it's important to know the age and hence physical and mental 
capability of the new dancers. Sautee's dance tends to be family 
oriented so the new (& experienced) dancers range in age from teens to 
seniors. I went to a ContraForce dance at Clemson University several 
years ago. The % of new dancers was around your 60%, but the new dancers 
were entirely college students. The caller was a student and not a solid 
caller. The new dancers took incredibly quickly to the dance. *60% 
beginners? No problem!**
*I was at a River Falls Lodge pre-covid dance packed with so many lines 
of dancers that it was easy to get confused with what's up and down and 
sideways. Dancers were mostly students (under 25?) and, I'd guess, 40% 
beginners. Caller came late so no beginners' lesson. The caller just 
started everyone off with a simple contra and built up from there. No 
muss. No fuss. Worked quite well. I believe the caller's calmness and 
just doing it worked ... never any question that it wouldn't.
**
Another data point is Lake Eden Arts Festival which, pre-covid, had 
5,000 people attending. Their gym, "Brookside", had contra dances with 
(at peak) some 400 dancers. Many (??%) dancers are drunk/high beginners 
who drop in since they're already there enjoying the weekend. They have 
fun for awhile then leave. Don't know what to say about it. It is what 
it is.
Another data point that I've heard about is a tourist oriented Virginia 
city in which the contra dance location was, for awhile, downtown in the 
tourist district. They struggled with older non-contra tourists 
overwhelming their small dance. I believe their solution was to move the 
dance out of the tourist center.
Wishing everyone well as we keep the dance going,
-Heitzso