I've been researching some customized HTML to put into my Blogger code to add per-post keywords in the meta element. I would like to know if this is good practice or should I continue to add the keywords in the "label" portion of Blogger.
I would strongly suggest not putting keywords in the keyword meta. That's the easiest way for competition to find your keyword research, linking and make attempts to outrank you. Your keyword should be contextually/title based, not a gimmick.