Hello Graham,
I see that nobody has replied to your thread yet and that maybe because this question is raised so many times and we all have our own preference on type of paint and colour.
I assume from the fact that you model 1/16th tanks that you know the colour you need and that it is likely to be either Dunkelgelb (RAL 7028) overall or possibly Olivgrun (RAL 6003).
Many people go to the Car paint specialists and take a sample of the colour they require and ask them to match it and many can actually provide the paint in aerosal cans. They normally require cash up front and I expect the results can be mixed. Do not rely on the RAL colour chart because it has changed since 1945 and 7028 no longer exists anyway

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My preferred way is to use White Ensign Models paint (I regard these as the most accurate) and buy sufficient pots to paint the whole vehicle. These paints are enamel but at least when I need to touch the vehicle up or add new parts I don't have to worry about having more paint mixed or matched correctly. I know this is not the cheapest method but if you are paying £4000 for a tank what is £75 on getting the correct colour paint. Of course you need an airbrush, light wind and a lot of patience for this method.
Send me a PM if you want any more info.
Kind regards,
Will.