What would be the best thickness for repair pieces?
And normal uncoated black iron or zincanneal?

thanks

0.9 cold-rolled will do for most patches. Zincseal is OK for welding, but not Zincanneal.

OK. Thanks Greg.

I always use 1.0mm cold rolled You can buy uncoated, but it is not as easy to get. Most steel places will have it with a phosphorous coating on it. You can sand it off at the edge welding areas,