What texture tools? Can you post a link?

"They're saying you have to use a release agent" Who are "they"? Is this from another web site? I'm just not sure I'm understanding your post.

If you mean tools to add texture to the hypertufa, you do that after partially curing your pot and removing the mold. It works best, in my experience, about 2 or 3 weeks after construction. It will still be sort of soft and damp, although it does depend on how big your project is I suppose. I've always used coarse wire brushes and and a screwdriver here and there to get ridges that somewhat resemble real tufa. If you're just asking about adding a little design to the concrete, like a concrete texture roller or the like, you'll need to do this before it cures. Most of the "texture" you see on hypertufa is from gently scraping/brushing away portions of the concrete rather than imprinting it.

The silicone spray works pretty well as a releasing agent but I must add one caveat: it depends upon what your form is made out of. Personally, I always use plastic (old polyethylene scraps) between my mold and my tufa to ensure 100% release. I don't trust just a spray on something as rough as wood.