As Jorge mentioned it takes experience to know your process and your materials...

Let's face it a SBR 5 is roughly equivalent to an N plus two development...there are some films and developer combinations that simply won't go there. A case in point is Bergger BFP 200 in any developer. Another is TriX in most off shelf developers. Beyond a certain development the overall density increases to the detriment of density range or contrast.

So for extreme expansion a limited number of film and developer combinations exist.

I don't think that this is a matter of a weakness of the BTZS itself...

For really extreme expansion such as rock patterns etc, I would be inclined to try a lith film such as Aristo APH. I would work with dilute Dektol. From my experience in masking techniques, I know this particular film will build a density range beyond any continuous tone film that I have encountered. A benefit of this material is that there are no considerations of increased grain as there is in continuous tone materials. The cost of the film is extremely friendly too.