More updates mean a higher chance of exposure. As long as you're okay with it, I'd say that twice weekly would be fine, if you're confident that you can continue to produce your work at that pace without being affected by burnout or your work losing its quality. If not, once a week is a good schedule to keep to as well.
As for me, my update schedule is entirely unpredictable. Lately, I've been trying to update twice a week (on random days) in batches of three comic pages, but we'll see how that goes. I do try to update at least once a week at least if I can't manage two updates, though.