Ben - I really don't have any settling. I was just concerned about it in case I put the filler over those seams.
As for above the windshield - it is solid, no pin holes - alhtough there are a few big ones for the visor.
So - from the experiences so far - body filler (metal to metal) is going to eventually crack out?
So a solution would be to weld the seams and then fill.
The ones I really want to get rid of are where the body wraps around to meet the door jams; the seams around the steps in the cab and the top seam above the back window.
I"m concerned that if I don't do this now - I'll always look at the truck and wish I would have....but then again - if I don't do it, it will give me someting to tackle in the future when we do the Bags, Big Block and other upgrades (don't let my wife see this sentence

)
thanks for the advice
- Ryan