I assemble my tandas most carefully, knowing that I may use the tanda again and again. I play music which has a beat that can be heard accurately by these dancers, in this hall; songs that are beloved and familiar to these dancers, but with variety in having a few new tandas and a few new songs (in old tandas), compared to previous milongas. I play almost exclusively music from the Golden Age, by the most popular bands (D’Arienzo, Di Sarli, Pugliese, Troilo, Fresedo, Tanturi, Calo, D’Agostino, and here and there Biagi, De Angelis, Canaro, Donato, Rodriguez, and rarely the others)
First, I select a half-dozen or so songs, from one band, with the same singer, from the same period, and in the same mood, and with similar tempo. Next, I select the first song, as one well-known to these dancers, and which identifies the band clearly; I know the dancers will pick a partner for the tanda based on the first song, so I want to make their pick accurate. Then I select the last song as the one that will create the most powerful and memorable dance. I arrange all the songs in ascending order of energy, which is often the ascending order of tempo also, throwing out those songs which don’t fit, and then throw out some more to get down to 3 songs (always my preferred tanda length, so that more women get to dance, and there is more variety of partners). Once the tanda is selected, and I have listened to the flow, I make the final adjustments, for similar loudness, similar equalization, and similar spacing (I like 3 seconds of silence at the end of each song).
During the milonga, I observe the Connection and Musicality of the dancers on each song, and combination of songs, and I note it, so that next time I can rearrange, replace and discard, to improve the overall Connection and Musicality.