That's pretty amazing that you got an accurate yellow from "bleaching" (meaning no dying at all).
I'm glad to know the vest bleaching worked so well, as I've been advocating it since the beginning -- alot easier than trying to 'make' a vest, and its already built for Hobbits. Frodo's coat will be even easier since it doesn't require any bleaching, just a straight dye.
I wonder if the color would be more vibrant with a dip in the yellow dye anyway. Couldn't hurt -- as long as you got RIT yellow dye. Not sure about the names, but one is a canary yellow color (good) and one is a warmer yellow verging on orange.
First, I would recommend getting the Rit Color remover. I am pretty sure it would have ended up more orange than yellow had I not used that. It stinks really bad though and the smell WILL hang around for a couple of days. Did that for 30 minutes then dryed it. It should be a pale pea green color when its done.
Second I soaked it for 15 minutes in a solution of 1/2 bleach and 1/2 water. Don't leave it in for too long or you may effect the fabric's integrity. Then dryed it. It should be a pale yellow when its done.
Third I dyed it in Rit Golden Yellow for about 5 minutes. The solution will be orange but don't worry.
After each step you should hand wash it in some laundry detergent before you dry.
Don't make the mistake I made tonight by drying your stuff in the dryer. There was some (albeit minor) shrinkage. Also the dye exposes the crappy job the factory in China did sewing this stuff together so some of the threads that were hanging around inside nice and hidden come out a bit like nose hairs on an old man.
But it really does work great. I love the stuff. It works great for any natural fiber. Just be sure that anything you are buying and hoping to dye is not synthetic...
I ran into this problem with my Joker vests. I could not find ANY vests online that were to scale and the correct pattern that weren't synthetic. So I had to either brush on thick paint or spray them to get them green. Which was a freakin pain to do.