i can use double overhand with no chalk up to 365 and got 405 with mixed with no chalk.
kroc rows are good, and i do plate pinches too. i got some gripforce a little bit ago, and i think they've been helping out as well.
i think in addition to deadlifting and heavy rows, you could probably finish off one session per week with some dedicated grip work and make some gains.
if you're stronger than i am, feel free to shoot holes in my theory.