You can only catch what is in front of you, 30 or 1,000 is no indication of you more an indication of rabbits in your area. In fact if you have had the permission for a few seasons and you are still getting big numbers, you may find the permission getting shared around....
Like Ideation says get a cur that can mark. I hate it if I cant take a cur along - sometimes you have to eat shit and ferret without a dog to keep hold of good ground (if you dont someone else will). Nothing beats watching a ferreting cur work and saves picking up nets from empty holes