I can’t speak about the dome’s COVID seating policy, but I am aware of how they came by there seating policy at the landmark theatre.
They worked with one of the largest venue seating companies who are considered as an industry leader in how venues can reopen and follow social distancing requirements. Using an enormous amount of data of the landmark (seat size, aisle size, traffic flow, rest room location, entrance size, etc) that they ran thru a number of testing protocols they came up with a number of around 800, roughly 27% of their normal capacity.
I would be truly surprised if SU isn’t using every available professional opinion to come to their seating number. The liability risk is too large for any sensible organization to ignore.