From my perspective some good info, some contradictory info and some poor info, but that goes for most sources. The problem with most articles and videos is that the writer/ speaker makes the mistake of believing that all growing locations are the same as theirs.
1. He says B118 is superior to all other root stocks. Plant it on clay soil next to M111 and tell me in 5 years it is superior.
2. He says plant your trees 12' apart, if you want them to form a solid wall in a few years then go 12'. No reason to plant trees that close to each other.
3. If you are going to plant your tree with the graft union at ground level then you have already planted the tree deeper than it was grown prior to receiving it. Typically planting a tree too deep can kill existing roots. Also you run the risk of the graft union getting buried and then the scion possibly rooting and losing the size influence of the root stock.
4.I can see why the guy heads back everything, over fertilizing leads to thin diameter, lanky wood. Can also lead to a lot of blind wood (no leaf or flower buds). Heading back every branch only leads to short scaffold branches with tons of lateral branches.
5. Some places may have aphids at leaf break but I have never seen them until mid to late summer here. I wouldnt spray unless you have a pest.