Yes, I saw you mentioned a 1" Heaset, which somewhat threw me.
However, this is the detail of how Kona frames ran with Headsets:
1988 – 1990 all models has 1” headset.
1991 - 1993 Hahanna & Fire Mountain had 1" headsets, all other models were 1 1/8".
1994 and onwards all were 1 1/8".
Your frame is a 1994 owing to the lack of a Triangle cut-out in the dropouts, and produced towards the very end of 1993.
See 1993 Fire Mountain below:
View attachment 554247
View attachment 554248
May I ask where you are taking the 26.6 measurement that you mentioned?
Pip