Thanks, Gary, Shaun, and STHV for your input. I have a Tamiya Tiger waiting in the wings, and I like to have all the bits I'll need to hand before a build. That includes paints and primers. This isn't always possible, however, especially with scratch builds say (improvising special bits etc.,), nor in the case of the Tamiya Panzer IV, I built from online spare parts and donations. In general, though, it's a good idea.
What I like about Tamiya models, and there's a lot to like, is that detailed build manuals for them are available for download, online. This means you can do a recce on a particular build, before you've even bought the model. That gives the prospective builder an idea of any potentially tricky bits.
The paint schemes for this early Tiger 1 are all based on Summer, in the Russian campaign. Tamiya suggest that the base colour would be Dunkelgelb (dark yellow) in all instances for 1943 models, and also for desert campaigners. This would suggest that 131 should have a base colour of Dunkelgelb, or TS-3 in Tammy rattle tins. As the dark grey, of previous iterations, strikes me as somewhat gloomy on the long Winter nights to come, I decided to go for the warmth of Saharan chic instead
Like Adam, though, I thought I'd base my build on Tiger 131 as I've already taken lots of photos of this unique beastie

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Gary, yes, I'm aware of how camo colours seem to change not only with age, but also with scale. The Olive Drab (SCC15 1944-45) on the Cromwell at Bovington, looks nothing like the SCC15 I was supplied with by Mig for my Cromwell build.

That's even though they are meant to have identical pigment formulations.
"Get your facts first, and then you can distort them as much as you please"- Mark Twain.