My guidelines for motorcycle trailers (Use at your own risk):
Height no taller than the motorcycle and rider.
Width no more than 6" wider than the motorcycle.
Trailer weight no more than 75% of motorcycle weight.
Tongue weight at least 10% but no more than 15% of trailer.
Total weight on bike (includes tongue weight, weight of rider and passenger, and gear in bags/trunk) should not exceed manufacturers recommendations.
Just remember pulling a trailer increases your stopping distance, decreases gas mileage, and can change the handling during curves and windy days.