Just figured out something that might be useful in designing paths. When laying the pre-made paving in the island designer app, the grass surrounding the path will overlap at the edges to give a more natural appearance. Much better than the harder edges when using DIY patterns. You can work around this using transparencies but it's a fair amount of faffing about to get it looking decent.
However, if you lay a designer app path first as a base, then apply DIY patterns over it, the grass will overlap both at the edges. It looks pretty nice.
I don't know if I'm making any sense at all right now.
Edit: Actually, looks like the custom path permit you can buy with Nook Miles might do achieve the same thing. Still, managed some nice paths with two layers so could still be useful.