I don't think there was a standard uniform colour for Spanish artillerymen at the time, although men probably wore coats of the same colour within a given artillery company. Technically speaking, there was no formal Spanish artillery branch until the early C18th and the establishment of permanent artillery
tercios in Flanders (1701), Milan (1702) and Spain (1704), all modelled upon the French
Fusiliers du Roi. The first official artillery uniform of dark blue coats faced red was not adopted until 1710 when the existing artillery units were merged to create a royal artillery regiment.
During the Nine years War, trains of artillery were created on a regional basis, with the field guns being crewed by professional officers and military gunners assisted by civilian contractors. None of the sources I've consulted (Gian Carlo Boeri's
The Spanish Armies in the war of the League of Augsburg 1688-1697, James Hinds'
The Spanish Army of Philip V and C.A Sapherson's
The Spanish Army 1701-1715) mention any kind of standard artillery uniform for the pre-1700 period, probably due to a lack of period sources.
Re the carriages, no source I know of seems to mention a standard colour, though I recall reading somewhere that carriages were tarred to prevent the wood from rotting. The painting below by Augusto Ferrer Dalmau (admittedly depicting the 1710's rather than the 1690's) shows the gun carriages in a natural wood colour :

Sorry I can't be more specific : there's a lot we don't know about pre-1700 Spanish uniforms. Others may have access to sources I'm not aware of though.