I've used home-built dollies for my boats, finding that one must be careful to secure the straps not just across the gunnels but also in a way that doesn't let the dolly shift aft while pulling the boat. I also found that having the dolly near the center balance point makes the end you lift be much lighter. The problem that arises if you go this route is how far over you have to bend to pick up the end and yet not too far lest the stern hit the ground. Lifting with a line affixed to the bow eye helps some, and having a much higher dolly also works, if this can be easily arranged.