I have the same situation, and question. Searching the forums at filehelpers.net, I found this thread (from 2007?!) with a response by Marcos himself:
Question:
In a delimited length layout, is it possible to skip some fields? For example:
ExternalSysId|ExportDate|FirstName|LastName
I only want FirstName and LastName, and don't want to clutter up my code with "dummy" fields?
Response:
The library dont have a built in feature for this.
You can make the fields private, the library will read the values, but you dont see them from your code =) If in the future you need these fields you can meke them public
So, using the Record Class Wizard to reduce the amount of required typing, and then making unnecessary fields private, looks like the best option at this point.