If you still get eratic numbers, you may have a bad or stretched cam chain. I had this on a GSXR once, every time you roll the engine over, the measurements changed. After you check a few times, it will be the same as the first time, and then will start changing agin.
I got a cheap 2nd dial indicater from Harbor Frieght that I use to check for top dead center on #1 cylinder. To check for top dead center on the piston, you take a reading at 10 degrees before and 10 degrees after TDC on the degree wheel, and half way in between is TDC. I leave it in place while I'm dialing in the cams, and that way if the degree wheel moves I can tell right away. also if you remove both side covers, you can put the degree wheel on the right side, and turn the engine over from the left, or starter clutch, side and it will lesson the chance of the degree wheel moving.