Is there a general rule to estimate the weekly costs of a show or to know how well it's doing? Is 300K good bad or ok for Fool for Love? I gather Allegiance isn't a runaway hit but is it at least treading water or bleeding (a little or lot)?
General rule of thumb, which someone will always attempt to discount and discredit is...
Small Play: anywhere from $150k - $250k / week
Large Play: $250k - $400k / week
Small Musical: $200k - $400k / week
Large Musical: $400k - $650k / week
Not many musicals with weekly running costs above $650k with the notable exception of the massive musicals, like SPIDER MAN and WICKED and even LION KING (if I recall correctly). Also keep in mind that any productions presented by non-profit houses have additional private support subsidizing a portion of weekly running costs, such as Roundabout and Lincoln Center. Furthermore, the weekly running expenses don't account for a contingency fund, which is usually 2% - 5% of the weekly running expense total, and any money "lost" when box office royalties are paid out from the gross revenue.