Figure out the grid (LDP-1450 text overlay)

Here is partially how Dragons Lair's lettering looks on the LDP-1450 (I only did the first three letters of "DRAGON").  This is captured at 720x480 but the actual horizontal resolution is somewhat arbitrary (according to the NTSC standard) and thus the 720 horizontal pixels achieved by the capture should not be considered correct.  The vertical resolution is always fixed at 480 lines so this must be correct.  The challenge here is to figure out the actual horizontal resolution of these letters, and to figure out at what factor they are scaled.

So... the question to the audience is, where is the horizontal grid and what is the horizontal resolution used by the LDP-1450 for these overlay characters?