I would say you to be more active, to test different options!
Active is good, in my view. The thing to avoid is "buzzing around" (as my partner would put it, "
ne sois pas une mouche"). If you're going to invite, either use a firm gaze from afar or – if verbal invites are fine for you – walk up from afar, ask, and then either dance or leave. But it's the kiss of death to kind of loiter nearer and nearer by, hinting but not asking. That gets very annoying very quickly.
A small milonga is also more easy to access and to get tandas.
That's regional. Here, your odds at the smaller milongas would be poor, because small milongas are small due to being the domains of cliques that don't open up much. Big milongas are hotbeds of "What the heck!" invitations shot across a room in a moment of clear sightlines. People know that in a chaotic mob, if a tanda doesn't work out, they're unlikely to be spotted being uncomfortable while dancing among 50 other couples three lanes deep, and they'll have a crowd to hide in afterward.
Try to spot dancers who have been dancing for a couple of years! They can dance but are still open for unknown dances. If someone has been dancing for 10-15-20 years they have most probably developed clear preferences and have a tango burnout of some degree. So it is more difficult to get dances there.
That's regional, too. Most of the more liberal inviters here are very, very experienced. They can dance with anyone – and while they
are burned out a bit, it isn't with tango but with the same partners. So, if a new face shows up, they're happy to see them and capable of dancing with them.
The cliques are mostly based not on experience, but on wealth and appearance . . . the "young, hip, sexy" clique, the "semi-retired with two incomes and money for tango tourism" clique, etc. They won't dance with you, but it has little to do with your or their level of experience. You have to meet entrance requirements based more on how you look, who you know, and what kinds of bragging you can do.