He already is running 2 18" saws. If he's cutting say a 25" tree into firewood I would much prefer standing on 1 side and getting the job done from basically 1 position. I hate having to march around and crawl over logs to cut through them, especially if they are elevated say maybe leaning on other trees or stout tops. Granted it will pull the smaller bar easier, but I'd rather let the tool work harder and my body less. He asked what size bar will it run and not abuse the saw. Actually I think you would be within reason with a 28" skiptooth chain, provided your not pushing it long hours in hot weather or using it everyday for professional logging. The longer bar does make it safer in the situations I mentioned also.