Looking for help building a seltzer system

[punkdigerati]

So the barbs on my dispenser tap are smooth and about 8mm. I was hoping a duotight 8mm fitting would do the trick, but my fitting came in today and it will not hold, the fitting is too loose.

I’m wondering if I saw he the evabarrier hose and clamp it down if it will hold under the pressure of a seltzer system.

a reminder, here are the barbs:

View attachment 743497

I know this was years ago, but for anyone else looking, John Guest Superseal is designed for clamping onto stainless tubes and should work well if Duotight isn't. I usually get JG stuff from freshwatersystems.com. When searching it can be best to use the filters to narrow down, as 5/16 and 8mm are both interchangeable in this context, but won't show up for the other if searched for.
For regular tubing DMfit stuff can also work well, but Duotight can be had cheaper for most fittings.