Replacing the pots might be a better idea. But if you want to change the resistors you just need to reduce them by the same factor. ie, your 5k pots are 1/20 of the original pot's value. So the top 100k resistor will become 5k, and the bottom 10k will become 500R. That's going to increase the current through that leg but it's still only 1.1mA or so.