What are the front ladder bar bolt heights from the ground with driver in the car? By the weights shown it has a ton of preload on the RR, +100lbs. That could account for some or all of the ladder bar angle difference. I'm assuming the angle was measured with the driver. No way you need 150lb springs in my opinion. This video is almost your weight with 122lb springs/6 cylinder bars.
No problem with weight transfer.
Doug
https://www.facebook.com/debby.kersantywright/videos/10211668943904056/?t=7
