Forgive my dumb question, but when you say that if Slavich Unibrom grade 3 is like Kodak's and Ilford's grade 3 you will pass on it, what do you mean? Is Kodak grade 3 and Ilford grade 3 too drab or too contrasty for you? This Unibrom is really the first graded paper I've used (except for some expired Ektalure but I don't count that) so I'm far from a good person to help ya, but
I will try. Also Laser Reflections site might say grade 3 is only avail, but I just got a supply from them and got grade 3 and 4.

Last below is a picture of a grade 3 (top) and grade 4 (bottom)...untoned, Slavich Unibrom fiber single weight...I put a reference next to it for you....