I think it's not just the top "bird" somehow (maybe a stiffer spring here would be nice?). For all the ropes I've tried so far, smoothest descent was when I've switched to a leather glove on the left hand, holding the whole zig zaggy bit and throttling the links with the leather glove. ISC recommends leather gloves and they seem to be right - either Petzl belay gloves or leather work pairs. For me, using a leather glove, the action on the bird became smooth as butter - just like the Petzl zig zag. Works both for rough out leather glove and for smooth cowhide work gloves. My normal rubber faced gloves don't work and I get jerky action, just like ISC says in their
instruction booklet. This took a bit of getting used to compared to Zig Zag but once you hit it, the Reflex is now working great. This is what made the biggest difference for me. Again Kudos to ISC Wales.
Addenda: There's this older
"Gloves" post on TB I remembered. In fairness to Reflex, I've had my ZZ inhale a latex coated glove some years ago so both probably have "pinch points".