Ganchos are inappropriate for the social floor. They are a figure created for stage performance. Why do you bother to teach them once a year?
I wanted to comment on this yesterday, but wanted to make sure I had my facts straight.
"Jorge Marquez, a dancer of Pompeya, is said to have invented the gancho."
Tango the Art History of Love page 257
citing Averna, Los olvidados bailarines de tango page 32
All I could find out about Marquez was a mention of him in the interview at this url
http://web.archive.org/web/20101129003800/http://totango.net/e_ginterview2.html
"There was one named Jorge marquez, In the 50s. he was a big name. He would come to teach me in the practica. People would come to watch. And he was very popular."
Thompsom writes that dancers in the 40s, he writes specifically of 23 individuals he identifies as the Club Nelson Men. "New moves were their goal."
"Most of the changes stemmed from Lavandina and Perroleo, who rethought tango."
"Further new sequences surged out of the clubs: raspadas, traspies, and boleos."
"In sum Petroleo and his colleagues challenged the dance status quo."
Here is more
Hence, he (Petroleo) undertook, with his friend Salvador Sciana, El Negro Lavandina, to invigorate the old figures. The two accomplices spent their evenings at the Nelson Club practicing. They excelled in inventing steps and streamlining the figures. They refine the ganchos so well that they are attributed with their authorship. It’s in the clubs of the barrios that the two milongueros test their latest discoveries
before they spread them to the milongas.
http://www.planet-tango.com/elfiru/petroleo.htm
So, all of this started in the 1940s, and it appears that it was taught in practicas and danced at milongas in Buenos Aires during the Golden Age.