Quake 3 Map Texture size

Im curious. I am working on an engine, that will be loading maps into a scene. I currently am loading only whole numbers similar to quake 3. I have decided to base my world scale on feet. So all my walls, and floors, and such will be on this scale. Im not sure what units quake based its maps off of but thats not realy important.

My walls and such are based on 2 ft squares. Well actualy 3 triangles per 2ft piece, but you get the idea. Know my question is this, what size of texture per that piece would look believable, but still kept small enough to be feisable. I am currently planning on using 128128 textures per 2ft of map. Or 6464 per square foot. Would this resemble a relistic setting? Anyone know the size of the quake 3 textures per unit??

Q3 was designed for something like a TNT with 16M memory. I think that a better approach is to target todays hardware. If the textures looks better if they are bigger so do I not see why you should use 128x128 textures. You can also try to compress them.