Anthony,
First of all welcome to the forum and good luck with the build. I have been toying with one of these for a while but whilst I prefer the standard of the Engles kit I prefer the look of a Type VII. I may try an Engles ballast tank in a Robbe hull, which has been done.
Anyway get as much reference material as you can, the Subcommittee web site is superb and well worth joining for a start, but there are a lot of other excellent U-Boat sites as well.
I have just finished a book called "Another Time Another Place" which has a lot of superb Type IX photos and is a very good read to boot.
Put plenty of pictures in the gallery where we can all refer to them in the future.
Best regards
Richard