I IMMEDIATELY noticed the difference in stiffness between the single vs. Duo Lyre's, since I switched from the Grey 82 Shore Single Lyre's, to the Black & Grey Duo Lyre's!
After owning both the INV6 & INV6HG's [first], and now the INV-HG mkiii's & SRS Duo Lyre Bases with the Grey & Black Duo Lyre's, I MUCH prefer the stiffer Duo Lyre setups! BUT, I ONLY use my Duo Lyre's to mount 2 & 4 channel setups, and NOT individual mics. So it depends on what you're running to determine which setup you need IMO!
If you're running stereo & 4 channel setups like me, I would just get the INV-HG mkiii or SRS Duo Lyre Base from the get-go, and be 100% DONE with it
However, if you're running individual mics, I'd definitely consider the 72 Shore Black or 82 Shore Grey SINGLE Lyre's for each mic. Or a single Black/Grey Duo Lyre setup for each individual mic, depending on it's weight capacity! Naks are heavy as shit with their internal batteries, so they might need a Duo Lyre for EACH mic FWIW