I was born and raised in Rockford,
@1buckie , on a 64-66 Glen Blue Imperial (that my dad bought in '73 at a garage sale)! ;-)
@effinUker I was also thinking that you might use a longish SS bolt with two nuts and a couple washers... attach it to the bottom grate with the bolt head extending *below* the grate, such that it wedges the grate against the remaining three straps and also against the bottom of the bowl. It would take some finagling, but you wouldn't need to drill through your bowl.