If I were designing video hardware and wasn't wanting to exploit chroma aliasing, I'd probably use a dot rate of about 10/3 or maybe 3.5x chroma, which would yield pixels with a roughly 1:1 aspect ratio in interlaced modes, or 2:1 in non-interlaced modes. If it wasn't necessary to go out to the border, that would yield a nice power-of-two screen size (512 pixels) which could facilitate the design of screen hardware and graphics hardware.

If I wanted to facilitate the use of chroma aliasing, I would probably use 4x chroma as a not rate and have 1024 logical pixels per screen row, and make the horizontal rate programmable as 227.5 or 228 chroma clocks, and the vertical programmable as 262, 262.5, or 263. Using 228 chroma clocks per line would yield vertically-striped chroma pattern. Using 227.5 chroma clocks on 262 lines would yield a stationary checkerboard pattern. Using 227.5 chroma clocks on 263 lines would yield an alternating checkerboard pattern. The alternating pattern would allow a better-looking display if software was able to render different content on even and odd frames, but the stationary checkerboard would probably look better than stripes if software could either handle having different objects for even and odd scan lines or else limited motion to two-pixel increments.

If I were designing video hardware and wasn't wanting to exploit chroma aliasing, I'd probably use a dot rate of about 10/3 or maybe 3.5x chroma, which would yield pixels with a roughly 1:1 aspect ratio in interlaced modes, or 2:1 in non-interlaced modes. If it wasn't necessary to go out to the border, that would yield a nice power-of-two screen size (512 pixels) which could facilitate the design of graphics hardware and software.

If I wanted to facilitate the use of chroma aliasing, I would probably use 4x chroma as a dot rate and, if memory weren't critical, have 1024 logical pixels per screen row (leaving some storage unused at the end of each line). I'd make the horizontal rate programmable as 227.5 or 228 chroma clocks, and the vertical programmable as 262, 262.5, or 263. Using 228 chroma clocks per line would yield vertically-striped chroma pattern. Using 227.5 chroma clocks on 262 lines would yield a stationary checkerboard pattern. Using 227.5 chroma clocks on 263 lines would yield an alternating checkerboard pattern. The alternating pattern would allow a better-looking display if software was able to render different content on even and odd frames, but the stationary checkerboard would probably look better than stripes if software could either handle having different objects for even and odd scan lines or else limited motion to two-pixel increments.