I have made several of the BAD-panels for my listening room. Both the curved version and the newest ternary version which also offers a "variable" -1 reflection function, besides the 1 and 0 from the template. I think they work great. Quite straight forward work, plus easy and cheap to DIY, all the holes are a bore to drill though.
To make Angus grid of 31x33 rows of holes suit a quadratic template, the hole pattern should be 19,19x18,03 mm for a template of 600x600 mm. Making it quadtratic 600x600 mm is only to make it sutable versus existing building and sheet standard dimensions (in the US module 24"x24").
Some pictures how they turned out: Salong Svarta Katten - Component forum - Page 8
and Salong Svarta Katten - Component forum - Page 11
The larger Ternary BADs along the long walls, each consist of 8 templates with varying positive and negative hole pattern, to decrease possible loobing. Size/pcs is 2,44x1,22 m (96" x 48") with some 4000+ 12 mm holes in each.
To make the improved ternary version is easy-peasy with a cone made of i.e. 3 mm thick rubber Ø 273 mm. I think you get the picture how, just by looking a bit further up in the thread (in case you got an F in Swedish ;-) )
Edit: I wrote an excel spread sheet to "tailor make" any sheet size with hole pattern to suit wall dimension in the room. Drop a line, in case you´d like to have it.