Theoretically loosening the truss rod will make the scoop higher, but on the Stagg EUBs the neck is to stiff without the rod, that it will hardly bend at all after making the truss rod completely loose. In that case the fingerboard would need some preparation from a luthier (don't try this yourself and don't do it on a standard neck/fingerboard Stagg EUB, because the wood is painted black there).
My Clevinger doesn't have and need a truss rod, even as a five string with Spirocore Mittel (which were on the instrument when I bought it used).
And the neck is smaller than on a normal 5-string since it was a 4-string originally but has a good 5-string ebony fingerboard.
I guess EUBs don't need a truss rod (unless weak wood is used for neck and/or fingerboard), because the neck usually is thick enough. But it's just a guess based on my experiences.
But anyway, first measure the scoop, then try to loosen the truss rod first a bit until it gets loose. If it is still loose after a few weeks, measure the scoop. If it didn't change the truss rod won't help at all.
So if the lower position notes (or only some higher position notes) still buzz after this procedure get your EUB to a luthier.
