Gave up on neckup device for now
 

I fashioned another suction cup held strap for my Fusion 12, but only one cup was needed for this one. No more fighting with the guitar. We'll see how it goes with some pieces, I only tried it with a celtic piece so far. The cups come with a wing nut as you see. I fashioned a crude "washer" out of a water bottle cap. Works fine.