A lot of people use clarified butter, but most of us just buy it pre-clarified as ghee. 
Definitely don’t use salted butter/ghee. However, chlorophyll is most definitely fat soluble, as well as water soluble, especially when heated. We use clarified butter for reasons that involve temperature stability and finished texture, plus more fat and less water makes for a stronger infusion.
I do a similar method using a water bath, but I use an electric pressure cooker to cut down infusion time to under an hour. The no-water infusion process is significantly better than most budder recipes, for sure! It makes for a much better flavor.
I usually go with about an ounce of bud per ½ cup ghee/coconut oil. It gets green, as it should, with that much bud. Mmmm-mmmmmm.