Test vs intervention by asking 'how many cases to sort out with one call at 3-level?' (2 calls if super playing case) If as precision vs 3D: bal, bal+, S, S+,H,H+,C, C+, SH, SH+, SC, SC+, HC, HC+ shortD, shortD+ the whole next level gets used to clarify. But if only 3-4 cases that overlap, simple. 1C <3D> ?? how to inform partner H yes, S no, game ok, slam no.