[john.gersh]

Using a stencil is one way to get standardized shapes. There's one for flowcharts at Graffletopia or you could make your own.

Another way is make new shapes by duplicating the first one you draw rather than drawing each from scratch.

A third way is to select all the shapes and enter the desired width and height into the Geometry Inspector.

I'm not sure what you're asking in the second question. Are you trying to make a shape by grouping lines? Group a shape with a line? You can do either of those.