First off, thanks for posting the vid.
Anyone who does not post their work has no bizniss jumping on you re quality etc. Also we cannot see the whole tree or know owner objectives, so commentary is unqualified from the start. Foulmouthed uninformed commentary says a lot about the source.
Well, since you asked, and given the above limitations, here goes:
About half the sprouts ("suckers" come from the ground) that you cut off may have been better off left on. Looks like you "skimmed" the entire inner third/half of the branches "clean", aka lion tailing.
Limbwalking to the ends can be useful to make some cuts, but it almost inevitably damages laterals that should stay. A pole saw can reach those cuts much easier and faster.
re onehanding, leave the chainsaw on the ground until you have made all the cuts you can (pole saw very ergonomic--up to 6" not hard on pin oak), then haul it up for the big cuts, which are typically low and interior.
o and diesel dirt, re doing 6 trims in 3 hours, get your boss to buy a wraptor. It will pay for itself quickly; do the math--if it saves you an hour a day that's ~$25/day so it's paid off in 100 days.