Hi Mike
That is how I placed mine, to be honest, 2mm might look a lot but that tube is set at quite an angle & only a tiny corner is left exposed, this small corner will get eaten away when you weld it
My top suspension mounts fitted like a glove, had I not set that out by 2mm I would of had a gap to fill under the bracket.
My alloy side panel fits just fine
Hope this makes some sense.