Has anyone tried Brass cartridge mounting screws?

  Dorkwad,that is very interesting with your speaker screws.I have the Pete Riggle bronze tone arm VTA adjuster on my tonearm,made a difference.

From Reference 3A's website

" Driver frames are fastened with softer metal brass screws to avoid resonance noise potentially generated by similarly hard metals" 

Perhaps that theory holds true for cartridge bolts. 

I use titanium or stainless steel screws with the Allen head; the brass is too soft a metal, I don't like it.
I am concerned only that they are non-magnetic.

Acoustic Sounds recommend titanium screws, and you can buy a set that includes different lengths of screws, on eBay for a nominal sum.  Do I necessarily believe that titanium (or brass) screws can turn a cartridge/headshell sow's ear into a silk purse?  No.  As someone else said, the only important thing is to avoid screws that are attracted to a magnet.

Lewm, If you do not have a detachable head shell using Ti screws are asking for it. Titanium galls like crazy. You might get away with it if you use anti seize but I would stick with stainless or aluminum hardware (only using like nuts!)  Some poor bloke is going to use ti screws on his SME V and permanently mount his cartridge. I wonder if Acoustic Sounds is going to pay for the mistake?