what are the ratios for milk chocolate ganache??
For Milk Chocolate it is 3 parts chocolate to 1 part heavy cream.
It kind of depends what kind of ganache you want. There is pouring ganache which is thinner and never sets up truly thick, setting ganache which is the 3:1 ratio mentioned above.
I use a 2 to 1 for semi-sweet chips to cream for ganache that I want to use as filling or a frosting because chips are naturally softer than regular chocolate. I use 3 to 1 semi sweet chips to cream if it's ganache under fondant where I need it to make a kind of shell.