I started by looking online and saw some great information with JJwargames who was just starting his 15mm Spanish for Talavera using AB figures - great pictures and lots of research. Seteven Balagan's painting guide was also a good start and giving figure choices - his army was more generic 1809. I bought a few figures from Alternative Armies Brickdust, Stonewall Figures (Capitan - which are more like 18mm thin AB figs), and Old Glory. It was 2 years later in 2023 I got to painting and buying more of the miniatures.
Here is the full Army as viewed from the side the battle terrain setup for Vimeiro.
Here is the image of the complete army from the front
I will be adding pictures under My 15mm Napoleonic gallery to show individual battalions over the next few weeks.
In 2023 there has been a large increase in website details to help with your own choices on a Spanish Napoleonic army.