I mix them till it looks right to me using the ESB promo photos. But id say its approx 1 X .75 mix for the POG and RLM76. the grey i literally just add a touch to tone it down a bit. I also add a touch of floquil light blue to make it a little bluer. I just do it by eye. Very little. again just trying to match the reference promo photos. There is a close match with humbrols for the floquil light blue listed on here somewhere so ive been told, so that may be the way to go since the floquil has been discontinued and hard to get, plus for the little bit you'd be adding to the mix its not really worth what it cost lol.