What were the other mistakes so I know what to look for?
You asked, so I'll indulge. Although I'm sad to waste another 20min of my life on his juvenile "I'm an expert" video. For record - I'm watching through it, pausing, and making these comments as I go through.
Throughout: He uses a roll pin punch as a drive punch. Great way to ruin the tip of a roll pin punch for its intended purpose. Doesn't really hurt anything since he's not driving them with force, but still a bad gunsmithing practice.
20seconds: He states the video is addressing ways to fix the problems that especially the older guns, "2000's, 90's, 80's guns had." I've worked on hundreds of Rugers the 80's through 2000's guns do not have any more issues than those of current production, and frankly, the current production guns are a lot more prone to have issues than the 1980's through 2000's production firearms. At ~45 seconds, he says "what used to happen is they'd have a lot of problems with the guns not being tuned right"... He obviously has extremely limited experience working on Ruger revolvers, otherwise he's just lying to make the shtick sound good for his video.
1min: He says a guy has to do a bunch of trigger jobs before - he feels - they can do a trigger job. Paradoxical oxymoronic statement - can't do a bunch of trigger jobs before you do a trigger job. Also, trigger jobs on Ruger's aren't difficult or time consuming to learn - $150 for a jig and anyone with a set of stones can do one.
1:45: Not incorrect, but way over-hyped. He acts like pulling ONE SCREW out of a Ruger New Vaquero to disable the RIP system is a significant action job. He spent more time talking about it and promoting his other video than the job should have taken to do.
3min: He checks the trigger pull, then says it broke at "about 4lbs." You can see on the screen the read out on his trigger pull gauge is reading 4lb 15.9oz. Then on the second pull, it reads 5lb 2oz, he claims "it's about 4 and a half, five pounds we're showing..." It's 5lbs on both pulls... Not 4, not 4.5-5... After the 3rd pull, you can't see the screen beyond the pound digit - which is 5lbs and unknown/unseen ounces. He does finally concede "it's breaking about 5lbs..." but then immediately follows "so 4 and 3/4, 5 pounds." The screen is visible for all 3 pulls, all 3 show 5lbs. Why would he lie about that for the video? At least at the end he admits it was 5lbs...
4:13: No "new model type" single action Ruger requires the grip frame be removed to remove the mainspring. He claims he had a few Vaqueros he had to do so with - maybe HE had to, but a competent Ruger revolversmith wouldn't.
4:21: You don't have to remove the cylinder to replace springs in a Ruger revolver. Doesn't hurt anything to do so, but it doesn't need to happen, the way he's doing this job.
4:40: He refers to the transfer bar as a "firing pin block," when saying he has to point the muzzle upward when cocking the hammer without the mainpin installed. Wrong terminology, anyone working on Rugers shouldn't be calling the transfer bar a "firing pin block.
7:17: He refers to the trigger spring retaining pin as "the spring hooks."
8:20: He mentions the poor man's trigger job, saying he doesn't recommend it because it gives "lost power"... But of course, he's referencing installing a "reduced power" spring pack. He's right to say the poor man's trigger job isn't great, but obviously has no idea why. If I recall correctly, the 30oz Wolff spring is actually LIGHTER - i.e. less power - than a single leg of a Ruger factory trigger spring. So his reasoning for favoring the wolff springs over the poor man's job isn't logical. The loss of power isn't the issue, it's the angle of applied pressure, which he obviously doesn't understand.
9:35: He's trailing off, but says that's how you can "work on your trigger springs to make them feel a little more smoother." Nothing about reduced power springs will make a trigger feel smoother. Only lighter. Lighter springs may actually make roughness more apparent. Dude's clueless and just trying to vamp for the video.
12:10: He talks about clipping coils on the mainspring again, using primer cup resistance as a reason to not reduce spring power. But he never mentions reduced preload at all, and he neglects that a clipped factory Ruger spring - only 1-3 coils removed - actually usually has greater force than a reduced power Wolff spring. In other words, he doesn't know that a shortened 17lb factory spring can be more powerful than a standard length 14lb Wolff spring - so his logic for why not to clip coils is misguided. He's passing on information he doesn't fully understand, and justifying it incorrectly.
12:12 (reiterated at 16:00): He says clipping coils and shortening a spring will shorten "lock up time". Not correct, in two ways. 1) More incorrect terminology: The time of the hammer fall is called "lock time," not "lock up time." Lock up timing in a revolver is a VERY different thing. 2) Reducing spring power - i.e. cutting coils or installing a reduced power spring does not shorten lock time, it lengthens it.
12:39 (reiterated at 15:55): He talks through how to grind down a factory spring, making an egg shaped spring cross section, possibly over-heating the spring and killing the spring temper, or leaving nicks, scratches, or gouges to elicit grain dislocations and cause spring fractures. Let alone the fact he's recommend letting it free wheel on the shaft, ensuring it will NOT produce a uniform cross section around the coils. Bad practice, irresponsible recommendation. Baffling to me that he'd recommend this modification over clipping springs.