Macadamia Milk instead of Nuts

That should work. I definitely would try it.

You could also just use 1.5 cups of coconut milk instead of blending the coconut with water. It may be a bit richer, given that coconut milk tends to be richer than the coconut + water blend here. (I know, because in Julie Sahni's early cookbooks, going back to the 1980s when you could not get coconut milk in the stores, her recipes call for soaking dried coconut and then blending it - something I did many times.)

Let us know if you do, and if so, how it turns out. Thanks! ;o)