I'm not going to try to answer the "assessing contrast without printing" part of your question. But I get good contrast using my Yashica C with fp4 rated at 100. I'm looking at some shots of a regatta that I did last year. It was an overcast day and I used n+1 at when I developed the fp4. The shots show good overall and local contrast, very good blacks and detail.

Others may disagree, but I would be somewhat hesitant about always using the yellow. I tend to think of it more as a tool for specific situations rather than a norm.

Mike