This is the internet. Since when I am knowledgeable on the internet?
What really matters when you do this test is seeing how quickly each nozzle fills up the individual cup. I couldn't tell from the video, but it actually looked like the first nozzle had a lower flow rate than the 2nd nozzle, but the 2nd one did have a more erratic flow pattern.
A more erratic flow pattern can cause a rough idle, but at power (and ROP) won't necessarily be as noticeable. A low flow rate on one injector is a problem, though, as that will lean out one particular cylinder. On an angle valve 360, you can actually get into detonation if the conditions are right, so that would be a concern.
While GAMIs work very well on Continentals, my personal experience on Lycomings is that they haven't done all that much. Now, some disagree with me, so again my statement based only on my personal experience.
I would take all 4 injectors out and soak them in Hoppes for an hour or two, then clean them off with brake cleaner and put them back in and fly it. Although the recommendation is to do this every 100 hours or so, I've found a number of mechanics (or owners) never do this step. It makes a difference. My bet is that after you do this, it will run better. Here's my personal story that convinced me on the benefit of injector cleaning.
My Aztec (like other legacy aircraft with mechanical fuel injection) had a "fuel flow" gauge that was actually based on pressure to the fuel distributor. As you know, a clogged injector will raise pressure in the fuel system since you're reducing the outlet flow rate, and in such a system will produce increased fuel flow. My Aztec had a fuel flow gauge like this:
Theoretically on takeoff both engines should be around 24 GPH. When I first bought it, one of the engines (I think the left) the needle went past redline and ended up about on the number 18 for the other side engine. The other engine went up around to redline. My mechanic insisted that the gauge was faulty, and I didn't really know enough at the time to argue with him, nor did I know enough to know what the performance of the plane really should be.
Fast forward a few months and I decided that I should clean the injectors since Lycoming says you should, even though my mechanic disagreed. So pulled all 12 injectors (6 per side), and soaked them in Hoppes for an hour. The Hoppes turned BLACK and you couldn't even see the injector in it, this was the case for all 6 injectors on the one side. The other side wasn't quite as bad, but was still pretty bad. After it was done I put everything back together and did once around the patch. Both engines went up to 24 GPH on the fuel flow gauge, and the thing felt like it had gained 100 HP on takeoff. The one side was so bad that I'm pretty sure it was running LOP at takeoff power. That said, it still ran smooth. The 6-cylinders (especially on twins) tend to run a lot smoother.
Summary: Clean your injectors.
