benevolntpirate: I've installed nGlide like you suggested but it's had no effect. Do I need to select the new driver in game somehow?
No, the game has no idea that Glide wrappers even exist, let alone that there could be multiple options.
I'm not sure about nGlide specifically, but in general you would look for files in the game directory with "glide" in the filename (e.g. "glide2x.dll") and make backup copies of those, and then (depending on whether the new glide wrapper was being installed globally or locally for a specific game) you may or may not need to add in certain glide files from the new wrapper's distribution.
I am *guessing* that you have installed nGlide globally, and so I would further guess that if you simply remove the existing glide files in the game directory to a backup directory, the new nGlide would then kick in.
You might want to check nGlide documentation, though.