From an earlier post I made: (if you do a search, you will find more as well)
As far as my paint, let me try to remember. Tamiya colors. A mix of Buff, Neutral (I think it is) Grey, a bit of Dark Yellow, and a touch of JA Green. Then it is lightened a great deal with White. Buff and Grey make up the majority of the mix, I add the other colors till it looks good to my eye. (Black mixed with White also makes a good Grey. No need to buy what you don't already have!)
50:50 Buff to Grey and then add the rest in combinations you feel are right.
But, you need to know that the base color gets changed a good deal from the weathering. I use various filters, umbers and sienna, and pastel washes to get the desired effect. This is another reason I lighten the base color with so much white, if not the washes make it look way to dark.
I'm lucky to have brought home some dirt during my various trips to the Territories where I have seen these vehicles in action firsthand. So, I use this for my weathering too!
If you guys are like me, you have seen what seems to be endless variations in the color of IDF armor. Sometimes it seems green, sometimes khaki, sometimes sand color, etc. In person I have observed that there are variations as well and I think the time of day, lighting, and other factors have a lot to do with the variations in the photos you see.
I'll be back there again this Fall, and maybe will notice even more variations.
My point is, do what looks good to you based on your references or ideas!
Steve