|Shako||Black with red rosetta, brass plate, white plume and yellow cap lines.||Black with red rosetta, red cap lines & pompom||Black with red rosetta, red plume and yellow cap lines|
|Jacket collar & cuffs||Red|
|Jacket facing & pipings||Red|
|Overalls||Garance (deep red)||red||white|
|Scabbard||white metal||black||white metal|
|Equipment||White with brass fittings|
In terms of the guns themselves they were probably like the Napoleonic guns, so your choice of light grey or stained woodwork, and black carriage fittings. In the illustrations below they look light grey.
The same guys in combat Notice both Turquí and white overalls in use
Artillery: 1. Major, 2. Officer
These officers have yellow cap lines, which might mean they are horse artillery, but it could also be an attribute of officers in general
Generals and staff officers wore what they liked, including different uniform styles and colours and items of civilian attire – the accompanying pictures should give you the idea. Also see figures 16 & 17 in Cairns (1994b).
Cairns (1994b) gives them Turquí jacket with white epaulettes and piping, red collar and cuffs. Black shako trimmed white, with red over white pompom. Grey trousers with red welt. Black equipment with white metal fittings. Cavalry scabbard is steal.
I’ve included a couple of pictures that NYPL says are Civil Guard from 1824-29, however, as that corps were only formed in 1844 (Wikipedia: Guardia Civil (Spain)) this is impossible. Either the pictures were from a latter date – which is what I suspect – or the men are actually from a different unit, possibly the Carabineros. Cairns does say that a British observer said the Carabineros wore black, and these apparently grey uniforms may explain that.
Cairns, C. (1994b, November). A Savage and Romantic War: Spain 1833-1840. Part II: The Cristino forces. Wargames Illustrated, 86, 36-46.