Of course, the factory had the equipment to suspend the entire body
and lower it squarely over the power train which was on a jig to keep
it square to the body.

Having said that, I've tried both methods and they are about equal.
Lifting the front of the body makes for some difficult angle with
respect to the front subframe. The rear of the car, especially the
long wheel base models tends to hit the ground before you have enough
lift at the front to fit the power train. Raising the rear to avoid
this puts the front at an odd angle when trying to lower the body. I
could go through a number of raising and lowering this and that
scenerios but I won't since I haven't found one that easily simulated
lowering the body squarely on to the power train. IF you can do that
then by all means fit the power train completely assembled to the
subframe. Otherwise it's a coin flip.

Cheers,

Kelley