First and foremost fish what you like and what works for you.
I went through this same thing when I first started using indicators 20 years ago or so, but over time I began to realize it makes absolutely no difference what color the indicator is. White, green, chartreuse, red, orange, black etc etc., the fish pay no attention to it from my experience.
They also could care less if you use a tiny wisp of yarn or a decent sized chunk so long as you don't bomb it down on their heads. If you lead them properly they could care less.
They do mind the heavy plop of plastic type indicators in flat water so I would and personally only fish yarn as it is easier to cast and there's no risk of the plop.
I draw from my lengthy career as a guide on the clinch and a trout bum who in my prime spent at least 5 days a week on the river.
The fly underneath and the drift you can obtain are vastly more important than the color of the indicator.