I've been following this thread and another that is closely related for a while and decided to dedicate a whole darkroom session to trying split tone printing yesterday. As I rent a darkroom I had preselected what I wanted to print, mainly material that had a full range of tones.
I had mixed results but the ones that worked really worked well. I had prints with punch for the first time.
It was noticable that the ratio of LC(00) to HC(5) times were nearly always 2:1 for the normal negs. My troubles started with negs that were over or under exposed (Hey I am Human) and even with test strips I struggled to get the balance without muddy highlights. I will have to practice the technique as I was very impressed with the ones that worked.