Thank you all for your advice. I found a few draw knives on eBay (I honestly hadn't thought about using that) and none on Craiglist (I live in a very small town, go figure), so I guess a follow-up question would be how to judge the item? I found one that's apparently from the 1880's, found some newer ones, and the pictures don't really show anything that a novice like myself would be able to see, notice, and say "oh no, that's not good" when looking at the pictures. Any guidelines?
What exactly is tillering? Just trying to get the bow to bend enough? I see images where people are hanging their bows up on these "trees", and slowly shaving portions (not the center, though) of the stave and then pulling the string down farther.