Do you have to put the ear numbers on the entry form when you send in your entries, or do you do that when they come onto the fairground? Bunnies can change their weight a lot in 2 weeks (sometimes just in the days they are at Fair before judging). I know that a lot of Fairs tag and take DNA samples a month or two before the Fair on larger livestock, but since you want to choose your meat pens as close to show time as possible, this makes it hard to properly select a good pen.
The rabbit shown is not a blue or broken though. Blue is a dilute of the black gene and is a solid blue gray. I would still stay with a NZ White for meat pens. Unless in the past 10 years the blacks have gotten really good in body type, which is possible, then the blues would not have started with exceptional meat type with the blacks as a foundation. I don't know what the cross would have been to produce a broken, but unless it was a good meat type breed they would have had to catch up to an established meat standard in the original NZW. Californians are also a good standard meat breed for meat pens.