Hello tel76,
I couldn't get a photo (not enough hands, with me on a ladder and with the top hanging over my engine, which is on a pallet sitting on some saw horses). I measured as accurately as possible from the exact inner corner of the top and B-pillar down to the exact outer corner of the B-pillar and horizontal seal surface near the hardtop latch. I got 17.75 inches. I hope that's good enough.
Tom Kizer