I put the lower dash pad on tonight and put all the underside screws in but left the side screws out for now.

I now have a gap in the door pillar edge seal. How far up does the edge seal go for a proper seal/fit?

Click to view attachment

just helping for the orientation of your picture

Click to view attachment

The welting is not a seal, it just covers the welded seam, around the door opening.
It goes from the rear window door seal on the targa bar to the front seal of the small triangle window on the door , there should be no gaps.
That seams to be about 12 inches short

That seal is way too short.

Both seals (upper and lower) should meet at about the red line in this pic VVV