Howdy,
The game ranch operations I know of in NZ range from 60 acres to 6,000 acres.
(We have two, one that is 400 acres and another that is 2,000 acres. I find the smaller block harder hunting, as there is a lot more cover.)

The cover is a variety ranging from thick beech/native rain forest to open tussock/grassland.
Some of the areas make a challenging hunt others, are easy.
Some operators release animals to order i.e. Buy at auction.
Others have an established herd and hunt the stags as they mature.
Some mix different species, others have only one.
e.g. Red deer.
Some are adjacent to natural range, others have been stocked from nothing to begin with.
To satisfy your requirements you need to establish the parameters that you are happy with, before you hunt.
Fenced hunts are definitely not for everybody, but really the only choice, if it's a huge rack you're after.

You'll find similar scenarios in South Africa.

NitroX , do you consider a two thousand acre lump of land with a fence around it to be enclosure shooting , or would you use that term for a ten acre pen ?

I dont see that a huge area enclosed by fence is any different to the same area surrounded by open farmland , as is the case in many of the areas publicly available in NZ . The terrain and cover will be the restricting factors in a large area . Shooting Basil the pet stag in the deer yards is not , however , what I call hunting...

I think we have to define "enclosure " in realistic terms.

Thanks for the information Tim , muchly appreciated , hope everyone reads it .