Ron, I think Erik gave the most accurate answers to your questions; however, I do have a couple of comments: 1) Erik said that 0db is the maximum sample value. Just a clarification, he means the maximum possible sample value, not the maximum sample value in a particular file. For example, for 16 bits, 32767. It's not a relative measurement, but an absolute number, despite the db label. 2) Erik also said that the Block Align is an internal detail. Well, yes that's correct, but it isn't anything complicated or secret. It is the number of BYTES for a sample (2 for 16 bits, 3 for 24 bits) multiplied by the number of channels. 16-bit stereo should give you 4; 24-bit stereo should give you 6. This information is redundant in WAV headers, and perhaps this is why Erik said not to worry about it. It would be better if it wasn't there because it's primarily an opportunity to screw up a program (or a posting!).
