Hi ruf0us,
Welcome to the forum - your introduction is the type I like the most :D
I do not claim to be an expert in the field and I can be wrong but the only depiction of a Hien with blue tail appeared on wingspalette website
WINGS PALETTE - Kawasaki Ki-61 Hien/Tony - Japan with the description
Unit:
hombu chutai, 244th sentai
Serial: unknown
Tokyo Defence, 1944-1945
Looks like color scheme of the model was based on this specific illustration.
To the best of my knowledge, all 244th Sentai Hien's that I ever saw in this type of camo, had red or camouflaged tails. Lightning bolt is also shown as red.
As for the model itself - good job!