I have the ECO 264. If you're not already doing it, try raising the bucket so there isn't a significant "head" or rise the fluid must combat before going through the lines. I was puzzled at how little liquid mine was pushing through the lines, almost nil, but the bucket and pump were sitting on the floor. I set the bucket on a milk crate and voila! Plenty of flow, through three taps and about 20' of associated 3/16" beverage line.
We are on the same page for sure. I planned to sit my collection bucket and sub pump on a kitchen chair so the pump will have less uphill force to move the BLC. Plus, as you mentioned, 1/2" silicone tube fits on my Perlick 650ss Flow control taps w/o the need for clamps. I had actually cut a short piece of this tube for a growler fill tube and been using this for a good while.