I would say lowest temperature is best, but 170 is fine. also, you know it is done when you twist a piece and it turns white--the connective tissue is popping loose from the muscle fibers, looks papery. It should be almost crisp, rather than "chewy". Chewy will happen as it cools, and draws moisture in from the air.
--edit to add: this also varies with local climate. in humid areas it will remoisten, in arid climates you might want to go for less "crisp".
If you don't use pink salt (nitrates) store it in the fridge, in an air tight container. Rabbit jerky is only unique due to flavor, any jerky recipe should give similar advice about done-ness and storage. The reason it is hard to give an exact drying time is that it can be affected by ambient humidity which varies by season and across the country.