- Click image to enlarge.

Alright, I think I may be on to something.
For starters, I have re-drawn Paraguay to have only two borders with enemy regions. Technically it still has three borders because the capital can be attack by the river. Note also the one-way attack into Argentina, which is historically accurate.
Next, the river has been brought all the way east almost to the coast - this is the actual course of the river (look it up!) and it makes a lovely boundary to protect the sud este region.
Finally, Goyaz has been redrawn to have only two borders as well, and the mountain range (now not a factor in play, but that's alright) put in the correct spot geographically. Impassable mountains replaced by the river (also geographically accurate). I think this allows for a better start, and makes it a decent +2.
I ran the regions through the spreadsheet and came up with the bonuses noted. I would have gone lower for some the five and six territory regions since they all came out around 5.7-5.8, but I know that my tendency is to low-ball the bonuses... at 52 territories this map is big enough to absorb an extra army here and there.

Legend: made the interior space larger and increased the size of the font; edited the text to drop one line; put flur de lys in the legend for color notation, which I think is nice since they were already in the legend graphic.
Oh yeah, broke up Argentina just a bit by putting in the river north of Puelches... if somebody really wants to start down there I thought I'd throw them a bone.
And another thing! Added some more colors by request... fewer greens.