I don't consider 1K maps that big... most cards have 256/512 VRAM these days anyway. Of course DXTC would reduce the VRAM usage to 25%... so I'd use as many as I need, typically at least over ten in complex FPS game with HQ textures and citylike enviroments. Exact number is impossible to give but you'll get the picture.
I don't generally speaking force textures to VRAM at all unless it's absolutely critical - like if you have a game texture you manually change (paint over or something) often during the game. Forcing things is usually bad - better let the DX and Drivers take care of the texture management.
I don't generally speaking force textures to VRAM at all unless it's absolutely critical - like if you have a game texture you manually change (paint over or something) often during the game. Forcing things is usually bad - better let the DX and Drivers take care of the texture management.