I got mine from Installation Parts as well.
On my setup for 1/2" silicon on 5/8 barbs, the 22-6 were the right size. 19-8 was too small. It wouldn't pass over the hose once it was on the barb.
I bought a bunch of different sizes so I can custom fit.
I also prefer these over worm clamps (I've replaced all my worm clamps). No tails hanging around to snag on. Also, I think they make the hosing look cooler. Not a real concern, I just like things to have a clean look to them.