Only acetic anhydride is unavaliable for one and anyone can make acetic anhydride. To make acetic anhydride you need acetone and a ketene lamp to make ketene which when touchs water becomes acetic acid. once all the water is converted into acetic acid or if you start with glacial acetic acid as your reactant with the ketene, the ketene reacts with acetic acid and each becomes acetic anhydride. Honestly if he can purify the resins as well as he writes out how to do it he can pull it off. Personally I'd love to try thc acetate if only for that fact that it is a white powder that dissolves in water, what cop would ever think to test water for thc? then again I'm legal in my state.
On a personal note I have every confidence in being able to make acetic anhydride but I have no conficence in producing laboratory grade pure materials. There for I would never try this myself but I would love to see someone with more lab experience do it.
One last thing, why does it seem like people love to tell some one else they can't do somthing like the ghb statement ghb is not cleaner it is sold as such online as an attempt to hide what it is, its precursers are used as paint stripper but so are the same solvents big pharma had whatever prescription pills API that you have ever taken in. Don't think that just because your pill is white it was never dissolved in acetone or benzene or chloroform or some other "paint stripper"