Hi,
I have been watching when I have time and the 40 is shaping up well.
A tip I picked up years back which may help is when you have applied filler and then the stopper mist the section with mat black from a rattle can and then lightly sand and it will show any missed pin holes.
I just watched you re-installing the springs and axles: The reason you have the 4 degree plates in the front is because your hangers are extended (possibly 2") and they bring the camber angle back to true. Also the front base plate should lip should face east/west thus affording some protection to the bolts. 60 ones have a deep lip all round and protect the threads and nuts from damage and IMO you have 60 series u bolts - wider spread.
The 60 series has a rubber insert between the spring and the axle, although to fit them you may need the longer spring pin. With the rubber bushes fitted, the inserts relieve some of the shock that would be currently borne by the hanger bushes and therefore make the ride better. The poly bushes are harder but do tend to develop a squeak in time. We recently re-worked my rear suspension and the ride is noticeably better with new 60 series inserts.
Can't help with the front suspension as mine is a combination of 60 series axle, PS, and P38 coils and radius arms.
As the hangers are giving some lift then your shocks need to match that lift and they will help the ride. Stock ones will, as you no doubt appreciate, will have lost a large percentage of their travel and therefore effectiveness.
Hope that helps.
Regards,
Rodger