One of the issues I've had with calibrating my Panasonic 65VT50 plasma is that you don't have a reference to use to verify that your calibration is correct.
Lets face it. You can spend months learning this stuff, buy what should be fairly decent equipment, get some great looking charts and the picture doesn't look that good. You think that's the way its suppose to be because the chart says so.
Having a background in photography which included owning a studio with an in house color lab, I had a reference to check the color, contrast, etc by viewing typical subject matter as well as grayscale and McBeth color checker charts. At that time, it was called a Shirley. Now with digital photography, there is an equivalent referred to as a digital Shirley.
I thought there would be something similar for TV calibration but when I checked there wasn't.
So I went about finding a way to verify end results and found that the iphone 5 and newer is considered to have a display that's fairly accurate. http://www.anandtech.com/show/6334/iphone-5-screen-performance
The ipod 5 and newer should be the same as they have the same screen.
I downloaded a digital Shirley to the iphone and also burn a copy of it onto a DVD to play in my Oppo BDP-95 bluray player.
Bring up both picture, zoom in and navigate around the image to make comparisons. There are a lot of comparisons that can be made but I'd focus on grayscale, McBeth color checker and complexions. Before anyone ask, your eye is far more sensitive in seeing differences but you have to have a reference to go by.
As much as I'd like to post the jpg of the digital Shirley, it's copyrighted. So you'll have to get it on your own by contacting a professional lab. In the meanwhile, if you already have an iphone/ipod 5 or newer and a reference bluray player, you might want to experiment with some people pictures.