Are Oak Whistles something that need be tweaked and if so, is the tweak similar to the gen. and others tweak? tweek tweek.
Its a bird thing.
I wouldn’t apply the generality to the brand as “needing” to be tweaked. It’s true that you could potentially get one that us a dud but I’ve found Oaks to be consistently good whistles, usually very clean. I only made mine tunable (which can be quite a feat on the oaks). One of mine had a buzz that I couldn’t seem to get rid of with tuning or breath changes so I gently softened the edge of the blade a bit and it went away.
You might try the blue tack filler idea. It made mine better by a bit.