For the semi sweet, I just used chocolate chips because I always have a jumbo bag from Costco. For the dark, I just bought nestle dark baking chocolate bars. I think they were like 60 or 65% cacao. You definitely need a food processor. It sounds horrible, but if you leave it on long enough, it does really make the chocolate into powder!
Re: JW
Here you go!
https://www.jasonandshawnda.com/foodiebride/archives/1046