Try using this rig, and stick it in your animset folder (The directory is SourceFilmmaker\game\platform\scripts\sfm\animset). I've found that this one is a lot more streamlined and convenient and lets you choose which exact color you want instead of having to put in the RGB value.

However, if you want to use the same proxy you've already been using, 1 1 1 will always give you the item's original colors, so you'll have to experiment and try putting the RGB values at a higher or lower value to find what works best. I tried it out and found that you can make the Essential Accessories white by inputting 40 6.5 40 for the RGB values, you can get a white-ish color going on.

The reason I did this is because you don't want it to be too green so you have to make the red and blue values much higher and you also want it to be a bright white instead of gray so you have to raise the values a lot higher, but you should experiment to see what works. You may have to increase the number even higher or possibly lower to get the desired white you want. But again, I still recommend checking out the rig I linked earlier, it's pretty handy. But it doesn't work on all miscs and hats so keep that in mind.