natural gas does not burn as hot as lpg so hence the need for bigger holes in the jets, get the jets changes and a new hose and then you may need to adjust the screw on the bottom of the burner (generally) to get the right burn. as for the plate just get a sheet of stainless cut or if you wish just buy a heatlie inbiult bbq and you will never have to replace it again, expensive but they are without doubt the best one around and aussie made too not cheap junk.