There are no longer any special considerations for 512k Trident boards. The driver is now configured so that they can use modes with normal timings. The available pixel clocks are halved compared with those specified on the Clocks line
Be aware that older Trident chipsets support a maximum clock of 65Mhz. Hence the best actual clock available to the color server is 32.5Mhz. This means, in broad terms, that the color server will require an interlaced mode to be defined for resolutions above 640x480. Newer chipsets (8900CL, 9000, 9000i, 9100B, 9200CX and 9420) support up to 16 clocks, and can support much higher clocks, which will allow 800x600 modes, non-interlaced.