I prefer the smaller reddish purple heads I get in the South of France or from organic growers here. It is impossible to tell without nibbling a little bit exactly how hot or sweet a given crop of a given variety of garlic will be. Crops vary, depending on the amount of sun and rain the year has had. Use your judgment. Garlic that cooks for a long time has a mellow, somewhat sweet flavor.
Raw garlic is sharper.
Hence, some recipes add garlic twice. The easiest way to separate the garlic cloves and to peel them is to put them on a stable surface, cover them with a cloth so the cloves don't jump all over the room, and bring a heavy pot or a large heavy knife down on them with a solid thwack. Lift the cloth. The cloves will be separated and the excess papery skin can be removed. Select just the number of cloves needed and repeat the process.