So do you use vos, or tu? Hace, or haz, etc..?
I think its much more complicated that "using" these "words". Speaking River Plate Spanish means speaking with a very different set of cadence, rhythm and stress patterns compared to other varieties of Spanish. It's a slippery slope. Come to Buenos Aires from elsewhere and its much more than a simple decision to slot in "vos" instead of "tu" or "hace" in place of "haz", or choose the River Plate "ll". Rather, you have to relearn almost all the most common second person informal verbs that the language contains, AND learn to speak with a different cadence, rhythm, and stress pattern.
Not to mention syntax; because Spanish syntax is much less important to meaning than English syntax (you can, for example, re-order the sentence "Buero no huye del moderno" at least four different ways without changing its meaning--a feat that is impossible in the most direct English translation), Spanish syntax patterns respond to style and regional variation. So, if you want to speak like a porteño, you also have to really listen for a long time to pick up the patterns that are common here but uncommon elsewhere. I think this, in part, is what we can admire in Dustin Luke.
An underlying issue is this: to speak like a porteño (as I say, much more than just a question of "accent") you can't help but tend to adopt the attitude that comes with speaking the Porteño way, and assume the risk that your friends elsewhere on the continent will turn their back on you or think about you differently. My associate here (who is Peruvian) tells the story of a Peruvian she observed (during a trip back to Lima a couple of years ago) in a Notary Public. It became apparent that the woman had been living for many years in Buenos Aires and had gone home to finalize her divorce. In the time she had been away, she had completely lost her Lima dialect and had learned to speak Porteño, with all the attitude that comes with it. Suffice to say, her Porteño dialect and attitude got her nowhere trying have her demands met by the staff of the notary office; she might have been better reverting to her original dialect and manners, but, I suppose, was unaware of much they had changed during her absence in Buenos Aires.