What is best practice for using the hair on curves?

I have a set of curves that are already on created on the surface of the intended fur, it's all very clean.
After picking the distribution mesh the hair from curves translate and scale together offset from the main mesh. 

I'm not sure if I should be leaving scale on the original curves or not?

Also, can I use a selection set in collbaoration with curves? I'd rather not have a second mesh for distributing the feathers which seems liek the only other option for controlling where the feathers will spawn