You can scale the the contents of an eps format file by adding the following:
<xscale> <yscale> scale PostScript command to it before the other commands in the file.
So to make everything 8 times bigger you would use:
8 8 scale This scales the following graphics with respect to an origin in the lower-right, so it may also be necessary to translate everything so the area where marks appear fall within the visible portion of the "page". Not surprisingly, that can be done with a:
<xoffset> <yoffset> translate These operations will be applied in the order order show. In other words, it will first scale the output, then translate it. Doing it in the opposite order would give different results, so it's important to remember this when figuring-out what values to use.
It's been a long time since I used ghostview, but I seem to recall there was a way to tell it to prepend a file with a preamble of commands it to each files being rendered, so you wouldn't need to actually modify the input file(s).
Conforming eps files will contain header comments that contain bounding box information of their content which can be very useful when transforming them. See section 3.1 Displaying an EPS file in the Encapsulated PostScript File Format Specification PDF file.