I wouldn't try to lead at Lo de Celia or Catchirulo because I felt that those two were the most traditional ones I visited and IMO they should stay so - When it is the clear opinion of the organizer and regular visitors, let it be so. I am gladly just audience there!
In many other places the space for me was the milonga tanda! That tanda is glad, playful and not so loaded so it was ok for the female leaders to enter the dance floor. Many times I could see one or two other couples at pista. But there was still difficulties to get a dance because followers are not used to monitor a cabeceo from a female leader.
It was fun to see the crowds reactions. During my milonga tandas there was very few negative expressions on the faces around the pista. On the contrary many onlookers were active giving us cheerful smiles, encouraging nods, thumbs up or positive shouts. At several occasions I could be sure about the persons being portenas and even many times portenos during this tourist season.
I think the tourists are driving this change, Europeans especially I think. They are used to see women leading and they are monitoring woman leaders even in Buenos Aires. The local rules are not so forcing for them so a female invitation for a dance is just an invitation as any.
I did not lead much during my month in BA but I was mainly experiencing the milieu. My biggest success was however at a newly opened milonga where I got a strong and clear cabeceo from a traveling milonguera. During our dance I expressed my worries about the organizer's opinion but she told me they were friends. When I catched his eye later he smiled to me, I relaxed and continued dancing. In the same milonga one of the portenas shouted to me her appreciation and asked for a dance. One other came to my table to talk and asked for a dance too. The pistas are little by little opening up for female leaders!
I consider this change to be historical. It is the first time ever when same sex couples are entering the pista. Earlier men were training at the practicas and women at home but no one has pointed out for me occasions where the same sex couples freely danced in ordinary milongas during earlier decades. If you know about it please tell me!