Mark - are you sure that is a flick roll? It looks like a vanilla aileron roll - though I admit to not have flicked an RV4 though I have slow-rolled one!
Pitch up 30 degrees, check and stick over.
To flick it, you need to momentarily approach or exceed critical alpha, so that when the rudder is smartly applied after brisk rear stick, the inside wing stalls and develops zero lift. Smartly push the stick forward to unload or the roll component becomes buried.