Maybe I'm wrong but I don't think WWI planes have problems with static judging.
It's the flying portion that's a problem, especially in wind. The reasons for this,
I think, are numerous and not all are due to biases. I've flown 15-20lb fast flying
airplanes as well as some light birds. When you plant the heavy ones on the
runway they tend to help, not hinder your ability to produce a scale landing and
taxi. Since takeoff, landing, and taxi, are typically 3 of the maneuvers flown,
you start with a handicap if you're flying a light airplane. Judges are going to
'count the bounces' and discount you for scraping a wing, etc. These are pretty
objective notions, not biases. This is not to say that the biases don't enter the picture but they aren't the only thing.
Cheers --- Larry