All of Koston's models fit .5 too snug I think. They've all been pretty narrow.
All Nike Koston's fit me TTS. The K1, K2, Hurache, and K3. Agreed on the narrow part, and I'm always a big fan of that heel to toe.
All that said, oddly enough I had to go .5 size down in the new Koston hypervulc. I'm glad I bought them at the shop because I tried the 10 on first and they felt long in the toebox. I tried the 9.5 and they fit perfectly.