There are some excellent builders in the area in the small to medium builder range, which is going to be your best option if the block has any slope as they will give you more realistic up-front quotes and maximise the potential of the block. Search builders with that kind of terrain, who work...
Suggest that you contact some custom builders with experience in that area or similar terrain, and get a quote. Custom builders are more likely to use stumps that work with building on a sloping block, so won't just dig a hole at a colossal price and bury a house in it. If you do get a quote...