You're welcome. I have a really bad lower back so it's not hard to figure out
Basically whatever the specific back angle the back should remain in a fixed position throughout the major portion of the lift and the lift utilizes hip and leg drive with the back playing a supportive role. Then at the finish the back straightens up.
Once you read that article you should be able to work on it and figure out you bread and butter way of deadlifting while keeping the major points in mind. A lot of little things about your body go into what you need to do to get the best leverage without comprimising form too much.
Many people put a lot of lower back into it. I call it the lever or torque method. A great majority of them think this is the proper way to do it and would simply disagree with me...the other part of them has simply never been shown or taught any differently. Once you start experiencing significant lower back problems, through whatever cause, you learn better. You'll likely have to lower your weight of course but in the end you should be able to lift more.
I'll get back to you on a squat video.