Thanks bschmidt for your input as well.
I got mostly positive response to my proposal :) *sighs in relief*
I also got the rates from him... his usual rate is £100 (approx $180) per minute, but is willing to drop it down to £80 (approx $135) per minute for me specifically. He also expressed his concerns, such as him wanting to be able to use the music to promote himself, so it's time to negotiate a little more; after considering a little more, I think I'll rather have him keep ownership but add buyout clause, as I don't even have any idea how much success will I have with game.
Bonus point to his music is that he designs it to be sequenced randomly, which makes it interesting. I'll also have to consider how much I need, but that's for another thread.
Once again thanks everyone for your inputs, this has been enlightening, and dealing like this is brand new experience.