I use an old WM single-blade edger beside my LT40HD Super. Except for very heavy flitches like 16' long, etc.
The carbide blade lasts a long time between sharpening and I figure it saves blade life and engine hours on the mill. A lot of engine idling time while stacking and flipping flitches on the mill.
I usually turn the log 90° at a time, and take off slabs/flitches just deep enough so that it will make a straight edge when I start milling the next face.
That way, only the first few flitches (from the opening face of the log), need to go through the edger twice.