Hi Mal,
According to "Tarnanstriche des deutschen Heeres 1914 bis heute" by Johannes Dennecke, the RAL designations for used collors were:
Rotbraun RAL 8017-today known as Schokoladenbraun RAL 8017.This collor can be mixed from following Tamiya paints: XF-10(Flat Brown)/65%; XF-51(Khaki Drab)/30% and XF-1(Flat Black)/5%.
Olivgruen RAL 6003-name still in use today- can be mixed from XF-60(Dark Yellow)/30% and XF-61(Dark Green)/70%.
So to paint your late Tiger with Tamiya paints you'll need:
XF-60(Dark Yellow)- straight from the jar for basecollor and as ingredient for Olivegreen,
XF-10(Flat Brown)-as ingredient for Rotbraun,
XF-1(Flat Black)-as ingredient for Rotbraun, but you can also use it straight from the jar for preshading/priming-should you decide to do these,
XF-51(Khai Drab)-as ingredient for Rotbraun and
XF-61(Dark Green)-as ingredient for Olivegreen.
I've found these recipe's on the web last year and was happy with the results.
Hope this helps