To answer all of these, it comes down to the theme you use in Curtains. I am using the "New Acrylic" theme from wincustomize. It is very basic, nothing fancy, no fancy buttons, etc so stock Window Caption buttons. It also has its own level of "blur" to be as close to Acrylic as it can. I also went and added the reflections image that was shared in this thread on top of that to have the reflective look to it.
Really, any theme can have blurred title bars if you know how to go into photoshop and manually create a gaussian blur to your liking. Here's an example of what my titlebar looks like. It's not entirely blurred but also not completely transparent either to where it's a distraction to have multiple windows open showing everything straight through.
If you're having trouble making the gaussian blur in photoshop then it might be how you're making it or something. I havent had any issues, just came down to getting the kinda blur I wanted.