Your answer brings up more questions
You speak of 'waterproof' and 'Durable Water Resistant' as if they are two different fabrics? 'splain please!!
And yes, a wet Collie that's been hiking in the rain or paddling in the shallows (he doesn't swim) WILL bring in buckets of water and if he's been lying around the campsite wet, also a couple of pounds of mud.
Since sewing and designing is not a problem, I'm leaning towards a pair of fiberfil quilts that can be thrown in a commercial washer and dryer whenever necessary.
For Dog nail resistance and easy of cleaning combined with two and half season weather, what would be a suitable combination.