I chose to go the cheaper route myself. I had some 2" aluminum angle in the garage, so cut it to 18" width and then drilled two rows of holes in one side to mount to the log, and then a couple more holes in the ends so as to be able to attach 2x4s. I bought a pair of 10' 2x4s, as straight as I could find, and used them. Drywall or deck screws mount the angle to the log and 2x4s, and a couple of short sections of 2x3 to fit between the 2x4s so as to keep the 2x4s from sagging and vibrating, and used longer deck screws there. The 2x3 cross braces are mounted to the 2x4s, but in contact with the log. This still requires a level for setup from end to end, and a square if you're making cants. It appears that unlike Bob, I only use the rails for the top cut. The initial cut becomes the guide for the next cut, and unless you're making live edge boards, you'll need to turn the log 90* to make a squaring cut.