CuisinartMSC-600 3-In-1 Cook Central 6-Quart Multi-Cooker: Slow Cooker, Brown/Saute, Steamer, Silver

I am struggling with which size to purchase. We are a small family of three with limited cooking space but think the 4 qt. too small. Suggestions?

most recipes say cook on low or high, how do you know what temp that is?

Is this crock pot lead free?

What size is best for a slow cooker? The Cuisinart comes in several sizes.