I decided to try ratcheting tie downs to lift the boat and flip her by myself. I knew the tricky part would be letting her back down because I'd have to release the ratchet with one hand and support the boat with the other. Before I went any further, I tried lifting first the stem then the stern with one hand. I'm no 98 lb weakling but I'm no muscleman either so I was surprised how manageable it was. You're only lifting part of the boat's total weight, so it's really quite easy.
I hooked one tie down to the lower rudder eyebolt and the other to a looong eyebolt through the stem that I'll use as a bow eye. Leave the bolts loose enough to rotate as the boat rolls over. To keep things really simple, I attached the upper ends of the tie downs to the brackets that hold the garage door guide rails. In my case, each bracket has two long lag bolts holding it into 2x6 rafters and since the boat weighs less than the double garage door, I was confident the weight wouldn't be a problem, but I was cautious none the less. With the door closed, (no weight on the rails) I hoisted the boat an inch or so off the dolly and then slowly added my weight to the rig by holding the overhead rail and lifting my feet off the ground. If anything was going to fail, I wanted it to be now.
Everything was good and solid, so I hoisted the boat to clear the dolly, held my breath as I moved the dolly from under the boat, and rolled her over. She was so well balanced, I rolled her with one hand. I padded the dolly with carpeting foam, moved it back in place and lowered the stem back down easy as could be. I added some supports to the back of the dolly so the boat would be supported under the keel and eased her back in place.
Start to finish, an hour and thirty five minutes. It was amazingly easy.