There are some main judges, I know jean tye judges dwarves often, and I see familiar people every time, I know that to become a judge it takes a lot of knowledge on the type and colours, patterns, often the judges for pet class are registered breeders who attend regularly, I have seen two lovey ladies I know helping with pet class
I think different judges like different things, I spoke to jean about my rose, if she should be put in main class, and she said how her size and type are good, some judges would mark her down for lack of yellow, and lack of spots, but at the same time her cinnamon is good.
Some judges have a colour they like, it's not like they downmark other colours, but some love sables, some love creams or goldens
If I was to ever become a judge, itl be long haired males! I always go for a wall and see the lil fluffs when I get there
Hope this helps