Smart Pot 1 Gallon Black 5 Pack

What are the actual dimensions (diameter & height) of this 1 gallon smart pot when filled with potting mix?

Can I use these indoors or will they create a mess?

what does the dimension 3.5 inches refer to on the info sheet? does it mean the thickness? or is this an oval shape and not a circle?

Is this an appropriate size for culinary herbs? I want to grow them indoors on a window ledge. Also, what to use under to catch water?