Having problems renaming maps

I want to change the map names on the intermission screen for the WAD I am currently making. The reason I don't want to do it for the automap is for compatibility issues. I want this WAD to be compatible with every known source port, stretching from Doom2.exe to Zdoom. I downloaded Doom's font from a website and added it into my font folder. I can type with it fine but I always get a "Bad Bitmap Size" error when loading it into my WAD. How big does the font size need to be? I tried using Paint and it didn't work that well. Thanks.

What I would do in your place (and I've done that a couple of times), is to run ZDoom in 320x240 resolution with MAPINFO.LMP loaded. In the MAPINFO you type the name of your map - obviously. And you simply screenshot the intermission picture with the name being proprely displayed. A few seconds of cutting and filling with cyan - an you're there.

And - for your inforamtion - you can change the map names on automap without breaking the compatibility much. AFAIK these simple DeHackEd features are recognized by any single port (not to mention vanilla, doh!)