[card_zero]

Thorn, Þ, seems a more natural choice. The rune is called thurs, even.

I guess there's katakana Sa サ and Su ス, if that's an improvement.

[RheingoldRiver]

yeah, but I was a math major and theta looks like a normal letter to me whereas thorn takes me a sec to realize what I'm looking at

I like the katakana idea, I wonder if I can train myself to recognize the Su one enough to start using that when I'm handwriting days of the week places