I make my own OD 1941 parson jacket color by mixing Gunze Hemp and sandy dark yellow and i think from the WW 2 images i have thats as close as i can get to the real color.However i just cant get belts and harnesses right mainly the canvas harnesses and webbing slung across the back and shoulders are my problem.i have been watching saving private ryan again and again and i have lots of images but i really need help here.what is the best mix for that OD shade ?.unfortunately i dont know how to post images of what i am talking about.

There is no one "right" color. Various shades of OD, nedium green, drak green will work. Due to different manufacterers, die lots, weather, fading, etc., the colors varied greately on the real gear.

This might help you some;
http://www.usarmymodels.com/guidetopainting.html