Yess I agree 100%It's good practice, especially with the metronome. Only 2 things I can think of right away are, practicing 1 part for hours isn't probably the best way, maybe do it for like 20 min and than do something else for a bit and go back to it. (just an example) Your brain needs time to rest and process what you did/learned. It's like that with everything, not just music.
The other thing is, you we're probably already tired as you mentioned, but I see your ring and pinky kind of go far out and low(under the neck) I do it too sometimes still, but if you try to focus on keeping those fingers high and close to the fretboard, it will probably help you get faster and all the good stuff.
I don't usually practice this way but I really wanted to push that last bracket and I guess that wasn't the best idea.
And yes, now that you've mentioned it, I see those two fingers slacking as well. I'll keep a check on them the next time!
Thanks alot bro!