Both of your rugs are too small. Use painter's tape to try out what you might do. I like rugs to slip under the front 1/3 of sofas so they really ground the room. Front feet only on it looks skimpy to me. You want the rug to extend past the ends of the sofa by at least a foot or more. At the dining table, go around and sit in each chair, leaving them pulled out when you move to the next one. If any of them are close to "falling off" the rug, then you need to go bigger. Generally, you need 36-42" of chair scoot and sit space, so consider that added to the size of the table top. If no one ever sits at the ends of the table, you can do whatever feels right when you tape out a faux rug.
Q