Why not go to some Argentine tango websites and look at the shoes there? I prefer www.darcostango.com/ because my wife and I got some terrific shoes there when we were in BsA in March.
Many tangueras wear shoes with smooth leather soles rather than the suede soles used in ballroom. I've spoken to several tango teachers and got different answers on that one.
I dont believe you really need stiletto 4 inch heels, but as a man, I really have no right to an opinion.
Jerry