WI: Treaty of Madrid (1750) more favorable to Spain in South America?

What if, due to whatever succession of factors (less successful Bandeirantes? Portugal gets involved in the 18th century continental European wars and gets a handing over of its own ass?) the 1750 Treaty of Madrid set up to demarcate the borders between the Spanish and Portuguese empires had yielded more favorable results for Spain in South America, primarily in what would become southern Brazil? I'm thinking of a consolidation of Spanish control over all of OTL's three southernmost Brazilian states (Rio Grande do Sul, Santa Catarina, and my home state of Paraná), portions to the south of Mato Grosso (roughly corresponding to most of OTL's Mato Grosso do Sul), and... perhaps chunks of São Paulo? The maximum i can see is the Tietê river, Spanish control over the city of São Paulo itself would already be way too much.
What would be the effects of Spanish control over all these new territories? This could be the foundation for some sort of Paraguay-wank, with the region's center of gravity shifted further eastward as it now has a coastline. Would the Banda Oriental (Uruguay) be added to this administrative entity?
What happens to Portuguese Brazil, now that it's been reduced in size?
 
isn't southern Brazil a bit remote to be run from Paraguay?

If contention over the region is settled (Spain would have to be reasonably aggressive in occupying the region to have the matter be considered settled) this butterflies the mid-late 1770's regional flare-up. Does this mean Portugal is now available to side with Britain in the American Revolution?

Next up is Portuguese takeover of Uruguay during the Napoleonic Wars. Does Artigas still have a power base there? If not, Buenos Aires does not enter into a deal with Portugal-Brazil to turn a blind eye while P-B takes it over. If P-B doesn't take it over, Pedro I (assuming things are still going as OTL) doesn't lose it and the confidence of his young nation, which has all sorts of ramifications for a butterflied regency period and for Portugal. Or alternatively, if butterflies allow Artigas to maintain his base, now you add on immense butterflies for Argentina.
 
isn't southern Brazil a bit remote to be run from Paraguay?
Well, kinda, and that's why i proposed that Spanish Paraguay's capital would move further eastward. Perhaps to Porto Alegre? The Jacuí river is a good west-to-east connection path from inner Paraguay to the coast of Rio Grande do Sul, if i'm not mistaken.
 
Well, kinda, and that's why i proposed that Spanish Paraguay's capital would move further eastward. Perhaps to Porto Alegre? The Jacuí river is a good west-to-east connection path from inner Paraguay to the coast of Rio Grande do Sul, if i'm not mistaken.
According to Wiki, the Jacui River is only navigable to Cachoeira do Sul, which is not all that far into Rio Grande do Sul.

If there were a reasonable way into Paraguay from Brazil, I'm guessing the Brazilians would have used it during the War of the Triple Alliance, instead of relying on the Parana River and getting stopped by the Paraguayan fort at Humaita.

If I recall correctly, Paraguay wasn't it's own entity, but under the auspices of viceroyalty of Peru, then Rio de la Plata, although it was largely ignored by both due to its isolation.

Don't mean to argue. If there's going to be a new spanish region, it would probably be centered on the coast from either Porto Alegre (which I don't think has a very good natural harbor) or Montevideo (which does). Most likely, it just gets added to Rio de la Plata. Any way you slice it, Paraguay remains isolated. That doesn't mean you can't transfer the wank to Rio Grande do Sul/Uruguay, which subsequently absorbs Paraguay. In pink on the map, Artigas (or a clone) could carve out a nice chunk of united states with Entre Rios, Corrientes, Missiones, Uruguay, Rio Grande do Sul, parts of Parana/Santa Catarina, and Paraguay (which gives access to a large chunk of the interior). These areas didn't particularly want to be dominated by Buenos Aires, and BA didn't want those areas to have any real authority/economic advantage in Argentina, so parting isn't all that ASB. The northern interior of Argentina didn't want to be under the domination of BA, either, but they're remote from this new colony wank. Together, though, the various regions could overcome the centrist minded BA, but now you have an Argentina wank under the aegis of the United States of South America.
 
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