You can construct your own grid rather than relying on the barbecue manufacturers to use high grade stainless steel.
You can buy stainless steel rod and cut it to the lengths you need for your kiln or project. Push them into soft fire brick at each end. Do the same with another pair of fire bricks and put one pair at right angles to the other.
In this way you can vary the intervals to suit yourself for different projects.
You could also put the rods on strips of mullite and weight the ends so the rod does not roll about while assembling them or when firing.
Alternatively, you can buy the grids available for various purposes. Not all are high grade stainless steel, but normally the spalling happens at a temperature that is low enough to avoid incorporation with the glass.