File-Survey 2.7 by Reudiger Khoel (Willcox, 1998) is one of the best .SEQ (and also .PRG and Binary) file viewers I've run across.  Not only does this view files with the option to print, it also supports viewing (and printing) in 40 or 80 columns.  On top of that, it supports most RAM expansions and can use up to the max of 16MB.

This disk image is mainly German, but there is an English version of File-Survey along with an English translation of the docs.  I also need to give credit for this find to Baracuda because it was on a disk image he sent over.