I have built two from old Sterling kits. The first one weighed 32 ounces with a Fox 35, and the second one had fairly light wood and weighed 28 ounces with a McCoy 35. The second one fly's really well, so I think 28 ounces or less is good. It has won several Old Time contests when others were having bad luck. LOL. My friend Andrew Hathaway just finished up one he scratch built with a Fox 35. We were out flying yesterday in the wind which was gusting to 20 mph, and it flew extremely well. His weighs 28 ounces also. But then Andrew can fly a Ringmaster/Fox35 better than I can fly most PA ships.