If you scale off the floorplan which is a CAD drawing, you should be pretty close. I've done it for other Thor floorplans and then confirmed it in person and they have always been very close.
In this case the rear bed slide appears to be a little deeper, and scales around 27 to 28 inches; hence your 30-inch dimension should be safe.
Hopefully you'll get an actual measurement soon to confirm.
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