unpopular
Been spending a lot of time on here!
do you basically have to guess WB and Exposure?
No. Not at all. There are color meters, but nobody really uses them. More important though is exposure. The problem is that there is no such thing as a "proper exposure". However, you can understand how the meter reflects data recorded, and make informed decisions about how an exposure is made to better represent the subject. I don't feel there is any guesswork at all. I know that my camera will produce a given luminance value at a given exposure within the specified spot meter region.