Allophony

Hi all,

I have a question about a language that's in my mind since this week.

This is the consonant inventory:
p    t     k  q   (?)    oral=20
ph  th  kh      h      aspirated
      s
      l
      tl

I want to include fronting/palatalization.
At first I thought of a system like Arawak:
t + i =3D tyi
th + i =3D ci  (c as ch in 'church')

Then I thought of k changing too:
k + i =3D ci
kh + i remains khi or Ci=20
    (C as ch in German 'ich')

Now /thi/ and /ki/ are merging to [ci]
and I don't want that to happen.
So I thought of /ti/ -> [tsi]
but what do I do with /thi/?=20
Any suggestions?

What is more likely?
/ti/ =3D> [tsi] ot [ci]?

Rob