Thanks. That is very informative on at least five points. But first Briggs & Stratton says use 30 weight oil. Then at the bottom they have a chart with 5 oil choices. 4 of which apply to where I live. I am inclined to go synthetic with frequent oil changes say every 40-50- hours. I like sythetic because a fraction of the synthetic will get up high and start lubricating the engine immediately. Quicker than straight 30 weight.
I missed the “mart” in Walmart above. Funny we noticed the same thing about the contradiction. SAE30 only- was old school.