I have two types of sawmills, a Woodmizer LT40 bandsaw sawmill and a chainsaw sawmill. The bandsaw sawmill can make cuts up to about 24" wide and saws fast and efficient. It also has re-saw capabilities. The Alaskan chainsaw sawmill can cut logs up to 66" wide, it is also very portable--take the sawmill to the big log-- and it can also sawmill oddly shaped logs. In December of 2018 I purchased a Lucas Dedicated Slabber which is a large chainsaw bar powered by a 23HP Briggs and Stratton Vangard engine and capable of milling a log up to 76' wide and 20' long. This sawmill is very efficient at milling large trees in to nice table tops.
Below are two videos of how I saw the big logs. The one on the left is how I did it from 2009 until December 2018 when I purchased a Lucas Mill Dedicated Slabber, shown on the right. It is almost 3 times as fast and more accurate, not to mention far easier on this ol' man's back.