Try Model Car World Automotive Finishes.
Their web site is:
http://ourworld.cs.com/mcwautofinishes/
They have the War Bonnet Yellow, but I didn't see the Ontario Orange. I may have missed it, their catalog of colors is as long as your arm. In any case, they will custom make any color. This paint comes ready to go without thinning in 3/4 and 2 Oz. bottles at reasonable prices.
I've used these several times and had no problems whatsoever. Dries rock hard overnight.
Pete