6% of the general population has some form of dyspraxia, or inherent clumsiness. About 2% of the general population has ASD. And only 10% of that 2% has measurable dyspraxia.
So stereotyping is based on 10% of 2% of 6%...
Inherent clumsiness and dexterity are traits like blue eyes or the shape of one's nose. It is not diagnostic criteria of ASD. And taking neuroplasticity into account can be altered through time and practice.
Check out books like:
Visual Thinking by Temple Grandin
The Violinist's Thumb by Sean Kean
Other factors that are much more directly linked to ASD are the sensory input issues of interopection. As well as the hyper and hypo awareness of certain input criteria like temperature, texture, motions, light, sounds, etc...
If you are targeting a market of those with impacted fined motor skills, look at those affected by dyspraxia or degenerative motor function (e.g. multiple sclerosis, Parkinsons, Huntington's, ALS, Alzhemeir's, etc...).
Something that is a measureable physical factor within the ND community (not just ASDers) is a fairly common comorbidity of hypermobile joints and skin. Traits of Ehlers-Danlo's Syndrome affect almost 20% of NDers, and NDer account for nearly 12% of the general population. And this is often a contributing factor to altered interoception (such has heightened pain tolerance and reflexive, hypertonic muscles with are a contributing factor to dexterity and other motor skills.)
I was in dance, gymnastics, and swimming. I excelled at all of them, especially swimming. I've also always been wickedly good at climbing trees, monkey bars, and balancing on swings. I never get a dog leash tangled (even when I am handling multiples), it is all about the context of the individual, not a stereotype.
My older sister is NT, but can't swim, turn a cartwheel, handle a dog leash without tangling it into a knot, or climb a tree, let alone stay on a swing...she is a complete klutz and meets all the criteria for dyspraxia.
I'm ASD1 with diagnosed EDS.