@ramsfan, the SCG cook grate is too small. The bowl measures 24 1/8" from where you suggested, edge of wall to edge of support tab. I measured across both ways and got the same result.
Support tabs could possibly be "extended" inwards by clamping a short piece of steel somehow. Or by attaching long bars or steel plates that extend all the way to the other side. Like how Craycort does it with their CI "ring" that supports their inserts in the middle.
But the bigger issue there, is that Weber won't sell anyone a SCG part without a serial number or other ownership of a SCG. It could be at least a year or more before 3rd parties offer that grate.
Been looking at replacement cook grates for the modern 26, to use with an expanded steel ring that sits on the tabs, creating a ringed "platform" for the larger grate to sit on. Craig recently said he has this setup for a flat top.
Right now I'm on the fence, choices appear to be spend money on the 25" NOS Grill Mate that lacks hinges but fits the kettle as-is, or $100 for Weber's that has hinges but needs the expanded steel. I'm leaning towards the latter since it offers a little more cooking room, a little more height, and still offers enough space under the lid for a turkey (again, from Craig's experience.)