While it is true that sometimes one can get away with a carryon bag in excess of 5KG, the OP is travelling out of IGU and CNF, both of which, like other smaller airports, seem much more strict than are GRU and GIG. That said, I have had my carryon weighed at IGU, GIG and GRU.

Don't try to go overweight unless you'll have a checkin bag to accept your extra items if they catch you. Otherwise you'll be leaving things behind. The only exception I have seen is women's handbags, which are rarely checked.

Elite status, including TAM Vermelho, does NOT help with extra flexibility. They're very, very polite, but firm about the weight limits.