I have these blades and the speed rating is based on my personal comparison with other blades. Going into detail, every blade has weight and speed tolerance. Also, there is marketing misleading. Many blades are presented as Off or Def but in reality are All.
I write about 980, 980XX, and Dr. NB blades in this forum. At some point I will write some reviews. Basically the same impressions as other owners. Good blades for modern defense, mixed play style, pips and magic.
Goriki, Goriki Super Cut and Goriki Danshi have similar composition - 7 layers of walnut. They are thin blades (4.9 - 5.1mm), with a hard surface, but most importantly, they kill a lot of ball energy. Especially at low force hit. Danshi is presented as an offensive blade, but is not. It has a little thicker middle layers and overall thickness, but the difference between the other variants is just 0.1-0.2mm. Not enough to make it Off. People catch that misleading and Nittaku changes the story: Off means not the speed rating but the play style. It is designed for offense. At 108g 960Hz good luck with pure offensive play... The control and stability is superb compared with any other blade that I have. The linear gears. The drell time. It is a wonderful blade, but is not as fast as the classic Off blades.
I tried Acoustic once and remember it to be fast and springy. Good near the table, and not good away from it. Nice woody Off- to All+.