I think you should candle to look at the air cell only, dont worry about the rest of the egg. Your nose is the best tool for culling bad eggs. Over time while checking air cells you will learn what eggs wont hatch by what you see in the rest of the egg an may choose to throw those out to make more room. At the same time you will learn what humidity is good an need to candle to look at the air cell less so you may stop candling all together an just use your nose. Both ways work.