Weld the upper ball joint in ?

I have been told by quite a few folks who have worked on A bodies that after I put the upper ball joint in the upper control arm, that I should put a spot weld in it to keep it in place.

That sounds a bit radical to me...maybe blue or red loctite instead ?

I also notice (and I asked this question where I bought the pieces) that the ball joint leaves quite a space above the knuckle when inserted. I was told that the seal which fills with grease takes up this difference and I should just torque the but to what ever the specification is.

Thoughts ?

Thanks
ian.