Hmm. I have used both DHCP and an assigned IP. Normally I start with assigning an IP since it's easier to control.
I'm not sure what you mean by script. When I get to the part to do dselect you just choose ftp and it will use your locations file (I think its location.choose or something to that effect-sorry no time to look it up) and will then query the location to find the file lists. Then when you update you get the newest list from the FTP site. I normally skip the dselect portion of the install until after I have the system running the base with an IP number on my network. Then I alter the locations file (check irc.debian.org #debian for the exact file name, also when the script runs through the install it will mention the file to alter) What to alter the file to can also be found on IRC. Again I apologize for the lack of complexity in my explanations I am not a programmer and new to Debian myself. JJN