I will add my experience. I did my first rear end rebuild on a 1956 Chevy truck when I was 15. It was a disaster. Started loud growling almost immediately. I was heavily involved in drag racing for about 25 years and always used professional services for the rear gears. After waiting many months for the Patrick's gears for my 1952 I decided to take on the task myself with the info available online. I had to take it apart 3 times to get the right shims. I ended up using less then half of what Patrick suggested as a starting place. I called Patrick and asked about the shims. I was told what I used could not be correct and I must have screwed up something. I put it together with what I thought was correct but was very nervous about the job at first. It has now been several years and several thousand miles later and everything is working perfectly. Other than Patrick scaring me I found the job to be relatively easy but I wasn't in any hurry.
