That’s a lot of story to cram into two hours, and in some ways I’ve barely scratched the hot surface of Tannahill’s ambition, which far exceeds the zany rom-com kitsch of Matthew López’s “Red, White & Royal Blue” and other gay royal fantasias. But if the author’s focus is too broad for his plot, with detours into AIDS and addiction creating a sort of disputatious blur, Chowdhury’s staging is as lucid as an oratorio. He perfectly sets up each actor for bravura solos that make their group scenes feel lushly choral.