Louie Simmons of Westside Barbell is one of the smartest men in training, but the dynamic effort method is the most overrated. It's not that it doesn't work, but it's not nearly as effective as a lot of people think. And the way most people do it is completely ineffective.
You're Probably Not Strong Enough For It
First you have to understand the population dynamic effort was designed for: super strong people. It was made for those who are efficient at producing a high level of force with their muscles and have good motor control. It's much easier for someone like that to be able to accelerate an external resistance than someone who's not as skilled at producing force.
Those who are genetically gifted to build a lot of strength are born either with a very high ratio of fast twitch fibers or an efficient nervous system. They also often have a good background in sports like football, requiring explosiveness.
These people can accelerate the hell out of 50%, moving at 0.9 to 1.1 meters per second. In their case, typical speed work might actually move too fast for what they want to train. But put the same 50% on someone who's not as gifted and the lift won't look explosive. It'll look a bit faster than a heavier weight, but not explosive.
I've seen people claiming to do speed work while the lift looks almost like a grind. Listen, a dynamic effort rep should look violent, not just less slow. Heck, I remember watching a video where the guy claimed "a 260kg speed deadlift" and it moved slower than my 90-95% max efforts (and I'm not a good deadlifter).
Usually people who suck at exploding won't be able to produce enough speed with a barbell when doing dynamic effort work. They'd need to use about 30% to be able to be somewhat explosive, but then the force production will be too slow to be of any benefit to strength. Those people need to learn to be explosive first by doing jumps and throws. Once they're better at exploding and have gained strength, then they might think about doing dynamic effort work.
First, Build Your Foundation
To clarify, the dynamic effort method works if you have a good foundation of strength and some experience with explosive movements. They're prerequisites. If you don't have those, you'd be better off building a foundation of strength through work in the 3-6 rep range and learning how to explode via jumps and throws (and Olympic lifts if you have a competent coach).
The main benefit of dynamic effort work for strong lifters is that they get to practice their competition lift at a higher frequency without burning out the CNS. It's not so much the explosion work, but rather the technical practice with low neurological impact that's the main benefit.
But the same can be accomplished by using a more traditional Russian approach of doing 5 sets of 3 reps with 75-80% using the normal lifting speed. Since the speed is more similar to a competition lift, it will transfer better.
Louie is a genius and has done more than anybody for strength training knowledge, and I love training explosively. But I don't believe that the traditional dynamic effort method is the best way for most people to do that. Also note that many former Westside guys have dropped the dynamic effort method themselves.