Cutting and welding a BBQ lid to make it narrower
I would try to cut as close to one end as i could so you effectively have just the  curved end.
Then cut out the &quot;couple of inches&quot;  off the end that you removed the end piece from and weld your  curved end plate back on.
This would be the most aesthetically pleasing but you could remove a section of the middle, you would have a weld bead in the middle of course.