By all means, please do share which device worked out for you. Congrats on the progress!
The VIS-06 is so strong, when you turn it past the 5.5 mark on the dial, it's literally unusable. There's a vent flap for exhaling and ~6 mark that vent flap will invert (goes into the device the wrong way due to suction) rendering the exercise useless.
FWIW, I'm on 0.75 having worked up from 0. Going to 1 seems so hard.
[0] https://www.aliexpress.com/item/1005001308855100.html?spm=a2...