Replacing windshield header

[michael.howell12]

My windshield header is rusted all the way across the top. I'm getting a replacement windshield frame with the header in tact cut about 6-8 inches down the pillar on each side.

Curious how others have went about this?

Should I cut just the header out and weld the replacement header in?

Or

Cut my pillars 6-8 inches down and weld the new pillars onto mine? Leaving the weld of the replacement header and pillars in tact.