That actually doesn't look bad at all. In fact you might have it. I need to watch the slow motion shots a bit closer. It's hard to ignore the rear end bouncing but you need to try. The only thing we are looking for is on the rebound when the car is on it's way back up. Are the front and back rising at the same time? Will they go back down at the same time? The chassis will remain flat if they are and it appears that it does. On a 2WD buggy the rear end will continue to pulse for longer simply due to where the weight is concentrated so just ignore that. It's pulsing at a frequency that isn't changing. It's duration at the frequency is and that's ok.

The first and third slow motion shots seem to show good balance. You can see a bit of porpoise happening in the second slow motion sequence though but it may have been due to the way it was dropped. Overall I'd say that's a pretty nice combination. Once you get shock oils worked out, you won't have the bounce problems anymore. We are only looking for suspension frequency right now. Not how long it keeps bouncing or how badly it may bottom out.

Here's one thing to try. Figure out approximately where your center of gravity is. Just use a finger on each side of the chassis and try to pick the car up. Move your fingers farther back if the front end is rising first. You'll probably end up somewhere near the center of the battery in location. Once you find it, push down with 1 finger on this spot. The front and rear of the car should both go down at the same time if it is balanced. Do this on springs only as shock oil can change this a little bit.