I think you're too hung up on the numbers. Only 70ms or longer works? That's just really odd, more so because you apparently are not confident in your ability to hear the difference. Horses for courses I guess.
For me compression is about catching the peaks and bringing them in line for fuller, steadier notes. The bass has plenty of sustain so there's no need to lift the noise floor there. Because I'm not limiting, the leading edge of the tone is not squashed at all just reined in.
Fast attack and reasonably fast release for me.