Let me tell you first off, you’re going about it in the right way. Playing with it is a battle. I’m sorry, but 3D Rendering is HARD! It’s never easy, no matter how you approach it o what tools you have at your disposal. So, please understand, everyone goes though the kind of frustration you’re experiencing.
Secondly, I hope you’ll download the materials I put up for the purpose of comparrison. Even if you hate them in your renders, comparing them to what you have now will help you understand what the different parts do.
Jacking down the specular is likely a good idea. I have taken to using specular maps for strength on Ambiance, SubSurface and Specular. Not just any maps, mind you, but high contrast maps like those that come with the Lana character. I use those now almost exclusively on my figures, even if they came from someone else with specular maps included. they’re usually not contrasty enough. I have the specular on my characters now dialed down to 25% with a glossiness of 50% or less.