" It cannot at this time be too often repeated; line upon line; precept upon precept; until it comes into the currency of a proverb, To innovate is not to reform"
-- Edmund Burke (1729-1797)
As anyone who has ever failed miserably to proof read their own work knows, "Best Practice" is whatever you learn first.
Xerces 2, version 11.0 was used for validation.
Validation Results
Past "Well Formed", what matters are outcomes, not display.