1) I use 19's all the time for more than what they were designed for.
It's heavy duty I can & do use the small 4.5 inch blade like a fireman's. Top edge less like to chip when you need to pry with the blade.

2) Waiting for a Stanaback & going to get custom sheaths for it to carry behind the back & on a 45 degree cross draw.
Only ever owned 1 & it was in ivory, didn't get to use it as it was the last knife I sold when getting funds together to adopt my Son.

3) 12-9 I know for most folks here it's to big but I like having a fighting knife available.
It is a big "light" knife for it's size for me.