I'm just going to leave this here for discussion.
This little article sums up a lot of the math we did at SDC with regards to the cost of performing in theatres. As we don't own our venue our break even would price us out of our market to the point of costing us substantial amounts to perform
https://www.middleclassartist.com/post/the-post-covid-concert-hall-catastrophe-why-audience-attendance-is-the-least-of-our-problems
It's an interesting article but it assumes people go to the theatre alone. I think many go with spouses, family members or close friends - people they are already in close proximity to. Spacing between family members would be unnecessary just family units. Not sure how many that would add to the scenario, perhaps bring it to 35 or 45% capacity? They would still need to separate rows and keep 3 seats between groups that come together.
I expect another consideration affecting capacity will not only be the physical distance between groups, but there may also be government mandates regarding allowed capacities at reopening. So, for example, if locally the mandate were "you can open but only at 25% capacity" (I'm seeing a lot of rumblings about that number in particular), then it wouldn't matter if it were mathematically possible to keep 6 feet between all seated groups and get to 45% capacity.
Alternately there may simply be hard limits on the number of people allowed to gather at once, and that would include the performers, crew, ushers. So a 2,000 seat hall may still be capped at 250 people for a time, depending on locale. I'm a little surprised the article didn't mention anything about how long it would take to get people in and out while maintaining distance. I expect even with significantly reduced capacity, the coming and going is going to take longer than usual.
A little of the groups and foyer are considered in the chat.
Like the current conversations about movie theatres the entry and exit to the theatre is an interesting one. Does post performance exit need to be on a row by row basis? How does one handle cloak rooms etc.