I think “过多” always be used in formal spaking circumstance, like television news, documentary films. the word can also be used in formal writing. While "太多” is more often used in oral spaking, and sometimes it may also contain some complaining emotion in it. For example, you put too much salt into the soup, it is very salty! ( 你在汤里放了太多盐了, 太咸了!)
If you want to express in a formal way , you can use “过多”(你在汤里放了过多的盐,所以它很咸。)Just a narration without surprising of complaning emotion at all.