Timber Framers Guild Forums General General Forum Questions Hewing setup

I am curious how others go about setting up a log on solid support and laying out lines to be hewn. There is a good amount of information on the hewing process itself but very little on the first steps of hewing : providing a solid base off the ground and then sighting and line preparation. I find it personally, necessary to get the supports really stable. Otherwise you cant reference the log on the lines or you have to keep resituating the log until is back to level. If I get the log to stay true to level and plumb lines the hewing becomes much easier. Am I the only that has trouble with log moving around too much on its supports?