I collect Colombia. I use the Temprano 1984 and my Barriga 1980 is used so much it is falling apart. I also use a 1926 Scott catalog. It lists some material that is not listed now. Other catalogs will help: Stanley Gibbons Part 20 1980, Michel and Yvert & Tellier.
For Venezuela, try to get a copy of Blanco.
Some information can be had in my tables:https://app.box.com/s/lpxrbt86tyhswwo7eg18
I have some other material that may help, so e-mail me atjerrybemail-Stamps 'at' Yahoo 'dot' com
and I'll see what else I can dig up. In the meantime, until you get a Barriga, feel free to ask any questions.