I have done some more investigating into my collections of German WW2 vehicles. My painting efforts started with a collection of 20mm Wargaming models. Some were resin but most were plastic. Back in those days (post 1987) I would have been using Humbrol German Dark Yellow. I sold off my stock of Humbrol's some years ago so don't have the product code on hand. This is a slightly yellow version of Dunklegelb and is pretty accurate as far as I remember. At this time I also made some 1/35th scale vehicles and which looks like I used the Tamiya version. The lightened version I used on the Tiger looks similar to the paint I used on my 20mm vehicles as seen on this Halftrack below.
Somehow I think I have too much for CoC and maybe should go back to Troops Weapons and Tactics (TWAT). I certainly have enough for What a Tanker (WAT).
So in conclusion I think I will keep on using the Tamiya XF-60 but following a suggestion I saw on You Tube I will add some yellow and white to the bottle. 25% of each was the suggestion but I will have to experiment with this first. I could just buy some XF-88 which is the new paint but have so much XF-60 I might as well use that up first.