I know I am going to get flamed for this, but here it goes…
I don’t see the problem with the jerk.
That is such a small thing. Lets not pretend like it is going to keep him from deadlifting 500 lbs some day.
In all likelihood it will correct itself when he gets more weight on the bar.
Also, there is no way anyone is going to “pull the slack out of the bar” until they get at least 3 and a half plates on each side. Even then, with a regulation deadlift bar, you are only going to be able to get at the very very most an inch. Totally pointless for him at this stage.
OP, with regards to your form, it is fine for your level of strength (especially when you consider that you are essentially hitting a 3RM in this video). You kept your back from changing its angle to the floor throughout the bottom portion of the lift (which is most of the battle for most people). Keep adding weight to the bar and gaining muscle. Start light, and when you stall, deload to 20 lbs heavier than this cycle’s training max, and start over.
DO NOT PROGRAM JUMP. Find a good program and stick with it. Start doing it as written (at least 3 months before you tinker with it), and over time make slow changes to meet your needs. I have done 2 templates of 5/3/1 in about 22 months of lifting, and had to deload only after I got out of the hospital because I started light enough to progress for that long.
Also, you don’t get points for slow negative portions of the lift, and I have never seen anyone lift any large amount of weight and set it down slowly between reps.
Always lift fast. Do not ever just mindlessly move the weight. As soon as you get to the bottom of the rep (pause for a sec on bench, DL, and OHP), then everything in you must fire as one unit simultaneously without saving any for the next rep (remember, you need to make this one first). It is something I have been trying to do with my DL for the last 6 months or so. (I went from 365x4 to 365x10 in that time period.) A hard/grinder at 405 is not as strong as a easy/fast rep at 405. There is a major difference between the two.
The most important things for you at this point in your lifting are that you are eating enough to foster strength development, and lifting consistently enough to cause the necessary response without getting injured.
But then again, I have only been lifting since Januray 2012, so I cant give you some type of advice based in my “extensive experience,” because I don’t have much.