I understand what the guy in the video is attempting to show, but I'm saying that his use of a homemade trigger scale is at best - severely suboptimal. To measure the trigger correctly, you should be pulling the trigger straight back, the same way your trigger finger would, and it needs to contact the same point on the trigger every time. You can get wild variations in pull weights if you're not careful - especially with Glocks. I make a point to use a silver sharpie to mark my trigger face to make sure I can contact it in the same place between iterations, especially since some time can pass as you disassemble and reassemble.
I've spent a lot of time swapping trigger bars, connectors, and a ton of other parts in Glocks to get a better pull. IME - removing the dimple is does not make a noticeable difference if you properly lube the the contact point with the slide. I've swapped trigger bars with Gen3 guns and noticed less than a quarter pound difference. I've only extensively messed with (2) Gen4 19 triggers, so my sample size is only 2.
Does every piece add up? Sure, but I don't believe that dimple is what makes the trigger feel so much different when compared to a Gen3.