Lighter weight, apron closure on left, and usually 4 yards are the norm. Length? I've seen all kinds of skirt lengths. A kilt should be fit as a man's kilt.
I think the North American people are no more strict than the Brits regarding 'rules.' it's just that our opinions are funneled through the narrow tube of kilt sites. The majority just wear kilts and don't bother with the discussions.