That mod looks great!
The other thing I thought of that would work fine- 22 inch rebar with the last 2 inches of both end bent to 90 degrees. It will fit fine across the weber grate and will distribute the weight evenly. I would try it myself (and probably will once I get a wsm) if I didn't already have a PBC on the way.
Weber One Touch Gold
2001 Weber Genesis that is no longer used since the OTG