[@Willy Vereb] It's a can of worms and I'm not entirely against it but maybe we could use volume or tonnage instead of size? My ships are rarely of the long cigar shapes so that wouldn't really be fair.

Alternatively, if nobody specifies the sizes then we can just adhere to the hierarchy and people whose ships are "treaty breaking" would have to specify so. (Or, when skirting, say what they skirt.) That way we can leave the technicallities behind while maintaining a semblance of powerlevels. As I assume most ships would also have a specified weakness.