In 2012 I salvaged oak, hand hewn, log floor joists, out of an old barn and decided to build my second cabin. To do the lifting I designed and built a pivoting yard arm lifting crane. All the parts were made from 6x6 timbers out of the barn. Getting the main beam up and onto the center pin (this allowed for 360 degree rotation) was a job but I managed using a gin pole lashed to the vertical. Also significant bracing to the cabin floor framing was required (this supported the main center support). This caused a lot of problems when trying to move around to do any work that required being on the inside. The two 2 x 8's in the front were in compression and the back 1/3 of the main beam was tied down with a ratchet come a long in tension (this kept the main beam level). I mounted the hay loft trolley and track to the bottom of the main beam (this allowed the log to be moved inward and outward for placement on the wall). A chain fall was attached to the trolly and used to lift up a log.
I would use two sections and attach the main beam to the scaffolding. Using the chain fall again to do the lifting. One problem was that as the load was lifted the leverage tipped everything forward. This problem was solved by adding cast iron counter weights to the back end of the scaffolding. I added a board to the bottom rung so I could slide the weights farther back away from the fulcrum point. This system worked very well. It was simple to move around and position. It was used to lift all the wall logs and then to raise the log roof trusses.
Fast forward 8 years and a couple of cabins and here we are with the third generation of log lifting rigs. They all were designed to lift 300 + logs and allow just one person to build a log cabin. Although having a helper makes things go smoother. The Sky Hook so far has been the best. It was only blind luck that the two trees used to anchor the cable lined up with the center of the cabin. Here a helper holds the tag line and keeps the timber from spinning and I pull it toward the cabin wall.
By hooking the ridge beam with a chain instead of the slings I shortened up the distance between the hoist and the beam. This allowed it to be lifted high enough to land on the support post tenons. Not having to deal with the weight of the beam made the work of lining up the mortises in the bottom of the beam pretty simple. All joints were then pegged together with 7/8" diameter Oak pegs.