I have never had much luck with chromatic lines. Except on rare occasions for me playing notes outside the key just dont sound right. I am sure with more study on this subject I would learn techniques on incorporating notes out of key within a tune, but timing, and placement for me is hit, or miss.
I would like to here a tune that incorporates two keys, it certainly would be chromatic, and not an easy thing to properly do, especially with band members who are struggling with one key, let alone two.
If somebody knows a song like that done right post it. I think many could benefit from studing the blending of keys, and which keys blend best together.