Hello everyone! New member here, and alpaca breeder.
I breed huacayas only. I can tell you that staple length varies from animal to animal, depending on health, age, genetics, and nutrition.
Our crias (babies) typically have 7+ inches in staple length their first clip. Adults generally have 4-6" staple, although older females, especially, do frequently have shorter staple of 2-4".
Often, suri will have longer staple length because they are shorn every two years instead of every year, a practice I definitely do not approve of.
It is believed that darker colors are coarser than lights and whites, but I have some blacks and a rose grey that put many whites to shame!
I learned to spin on a drop spindle with the fleece of my oldest girl with a 2-2 1/2" staple. Right now it's still a single, and is rather bulky, but has really wonderful handle. I need to spin up some more to have enough to do something with!