The problem with figuring out Soviet colours is the relative lack of colour photographs. In addition early colour photography had severe problems is capturing true colours. Not that modern film or digital colour reproduction is perfect, just better.
I have seen reports (however true) that within a tank brigade you could see the proverbial Forty Shades Of Green. In such reports I have seen reference to tanks painted with civilian tractor green and such like. As Soviet industry recovered from the evacuations, that became less common and uniform colours became the norm.
As for winter white wash schemes, they were usually were literally "white wash". Such schemes were usually water based pigments (like lime mixes) that didn't adhere very well over time. So at the end of snow conditions the white scheme was normally patchy and only needed a vigorous scrub to remove. In some cases when the temporary white was unavailable, civilian style oil based paint was used and would be harder to remove and would require overpainting, but that type was less common.
As to non winter colour schemes: Taking the German 3 colour scheme as an example, the base yellow was applied at the factory. The crew was supplied with tins of red brown, olive green and base yellow to allow the crews to camouflage according to local conditions (but note that from late '44 the 3 colour schemes were very often factory applied). It was up to the crews to supply the method (brush, spray or worn underpants on a stick) and the solvent. So the red-brown could vary from reddish deep chocolate brown to pink depending upon whether the pigment was mixed with petrol and applied with a rag or mixed with water and sprayed on, respectively. Factory applied schemes on the other hand were noted for their uniformity (eg so called ambush scheme). Allied to the uniformity of the late war factory schemes you could see colours not in the standard repertoire, like many Hetzers (Czech) that had locally sourced pigments.