Bob, other than the stop drilling, the factory manual tells you to do exactly what you first put down. Dress the crack, weld it, and weld a plate over it. There are specific recommendations for the shape and attachment of the backing plate depending on the area of the crack and how far it goes, but you're on the right track.
1956 GMC 370 dump " 'Tater "1970 VW Volksrod "the Black Bomber"
2007 Chevy Avalanche
2020 Jeep Cherokee Trailhawk,
2005 Harley Davidson FLHTCUI
I dig all cars, old and new, whether they were hammered out of American iron, German steel, or Japanese tin cans. Being unable to appreciate them all is missing out on a world of great things.
But thats just MY opinion! :P