Rob Nierse wrote:
>So I thought of /ti/ -> [tsi]
>but what do I do with /thi/?=20
>Any suggestions?

What about switching it around. To me, it makes more sense for=20
an aspirated stop to have an affricated variant. In other words,=20
something like:

/thi/ -> [tSi]

You could also keep the aspiration difference between /ti/ and=20
/thi/. Hence:

/thi/ -> [tShi]
/ti/  -> [tSi]

If I'm not mistaken Irish has palatalized /t/ and /k/ that do=20
not merge. So you might want to be inspired by Irish. It goes=20
something like this:

Dental   /t[_G/        /t<retracted>_j/
Velar    /k/           /c/

You also be inspired by a more Japanese-like model.

/t/ -> /tj/
/k/ -> /kj/

Your options are almost limitless.

-kristian- 8)