Tony,
I'd never tried makecfg.exe before, so I ran it now and got the new fractint.cfg file, thanks. Even so, having updated my sstools.ini accordingly and then tried to manually select another screen size using Delete from Fractint, no go above 480x640 pixels. I also made my Windows screen size larger, all the way to 1024x1280, but that also didn't help, even after a restart.
Which version of Windows are you using? The NT/2000/XP variations are, for the most part, reluctant to relenquish control of the video card at the level that Fractint needs. That said, I have an ATI card that runs Fractint fine at 1024x768 under XP (except after hibernating). And, I have two Intel video cards that won't run Fractint above 320x200, also under XP. Jonathan