I got some reflective tape and Texas flag map decals on Ebay to make night riding a little safer. I just ordered a Yamaha decal with letters only and no background. When it gets here I'll put the Yamaha decal over the blue reflective tape.
While adding reflective strips and high vis elements to a helmet won't hurt anyone, don't have the illusion that it'll all of a sudden make you visible. If they can't see a bike with lights and a person on top they aren't going to see a helmet.
High vis or white is statistically proven to reduce accidents and the helmet is the best place for it. The jacket second. The color of the bike makes no difference surprisingly. Rock a white helmet. They stay cooler anyway. I bought mine used so was stuck with black so I plastered it with a reflective kit. My daughter has come upon me on the road without expecting who it was and told me my helmet jumps out like a sore thumb at night 100's of yards ahead through the rain.
Anything you can do to make yourself more visible is definitely a good thing but no matter what, I ride every ride like I'm completely invisible.
Always assume the car is about to do something stupid... because they usually do