Engagement picture questions...

We have Steve from Patken,,we can have Doug for our engagement shots if we want the nudeyones..which I love..but I kind of want soem nice pictures also and we do need to meet Steve anyhow..my questions are..I knwo an 8 x 10 comes with the package, but whats an average people usually spend on buyng the other engagemant pictures..they take a few right? Do you keep those proofs? How much do you tip the photographer for taking teh E shots? We will probably be doing this soon, so any advice would be great!