I have done some SV ring training and went the the WDA Seiger show last year. I heard the opposite about muscling/body weight, although we weren't specifically discussing working lines. I have been told that judges want lean, well-muscled, powerful appearing dogs. The prep for these big shows involves a lot of conditioning with weight pulling, hill work, even underwater treadmill. I'll be going to a much smaller SV show here later this month and will see how it differs.