According to E How - Combine 2 parts cement, 1 1/2 parts perlite and 2 parts coir fiber in a plastic bucket. Coir fiber is the fiber leftover from coconut husks when coconuts are harvested. It behaves similarly to peat moss and is used in many areas as a peat moss substitute, according to Washington State University Extension.

I have never tried but I believe it should be just fine. Hypertufa is trial and error. It does not look great the first time, but eventually you get it the way you like.
Here are my three don't for hypertufa
Dont mix too wet, dont make it under 50o F, and dont allow it to dry to fast.

Here is a link that might be useful: my blog