Primarily, it's up to you. The best way to show up here on Tapastic is uploading quality content often. It doesn't have to be every day, but several times a week when you're starting off is helpful to gain new readers.
Of course, I would have a buffer in the meantime, that way you can be working on pages and never get behind. In your case, you should post however you want, but I would finish a lot of your comic before starting your upload schedule.
Take @AnnaLandin 's example of being several pages ahead and posting twice a week. She's up there in reader views and she's basically got it down pat when it comes to scheduling her time.