Bulkhead repair panels

I need some door pillar replacement parts for my bulkhead and am undecided whether I need YRM 1.2mm steel or Land rover refurb original 1mm steel. The difference is about 50 quid against YRM but its thicker. BUT it comes painted and I want to galvanize so I would have to remove the paint.

Also unsure about the extra thickness in terms of lining up everything.

I have been making my own footwell sections in 2mm and its not a problem as it don't have to line up when butt welding.

I do have concerns about butt welding thicker sheet next to thinner especially along the top of the bulkhead where the rubber seal goes under the windshield.

Any thoughts greatly appreciated!

Thanks