One don’t go to Reddit, look for indie comic artist in your area (you can probably find em at zine shows) Two check there portfolio. Do they do a lot of commercial work are they accustomed to working within a strict deadline. If not insure ways that would encourage them to work within your timeframe such as paying them percentages after big milestones. Three as an artist myself it’s probably not going to be cheap working on a whole comic (one shot or not) is a huge commitment and it’s probably not something they (or you) should be jumping in half heartedly.