Hey John, that is just about exactly what I have, the bed is a big one, and I got the largest hardware I could get, these things are about 8" long, a good 1/4" thick and about 3/4" wide, mortised into the frame, just like the pic you posted. On the headboard & footboard, they are into 5x5s and I put 4 hard beech dowels about 1" in diameter into the side of each 5x5 for the screws to get a good bite on, predrilled the holes, and used an impact driver to drive the screws, the screws are a good 3 1/2" long VERY thick screws, about 3 times as thick as the normal wood screw, but not as thick as a lag screw. Into the bed rails, same thing, the bed rails are 2x10", same thing with the beech dowels, one for each screw, predrilled etc. The inside of the rails have a ledge rabbeted into the rail, to provide a good solid ledge for the platform the mattresses sit on, the platform is screwed to the ledge, all the way around, and the whole unit was rock solid.
About 3 months after finishing the bed, it started to squeak, get into bed, or get out of bed, "Squeak"
I took the whole shebang apart, and tightened up the screws, this time using some white glue on the screws to hopefully get them to not back out............... six months later.......... "Squeak.......
I really thought I'd over engineered it, but I had not, bed bolts would have been much better............. I think
For a smaller bed, for a child, yeah, I'd use them again, but for a kingsized bed? Nope, never again!
The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails.
William Arthur Ward