best answer
How is that the best answer, on a 100 yard slip the dog will be tiring before getting there
Its the best answer cos its the only answer. Read the question properly.
Derbylad and Chid have gave you the best answers though, there is a lot of factors to consider when planning a slip as Derbylad said
For your dog I would give it short slips all it's life but I slip my deer/greys and pure greys up to 50 yards, is that better for you