building a qrd diffuser

Hi, I just finished reading about diffusers from Alton Everest's Master Handbook of Acoustics and really want to try to build one. However, I cannot find plans or how-to's on this subject anywhere. I do not know what materials to use and I would like to know the relative difficulty of building a 4311 vs a 1925 for instance. Also, with a 4311, there would be no need for absorption behind the diffuser (ie Ethan Winer's design). Is this correct? If I decide to build one with less bass diffusion, how would you incorporate the bass trap behind it. Everest never went into any detail on this. Any help or links to good plans/guidelines would be appreciated. Thank you.