Since the centers are in a R-H wave, you are applying the "Ocean Wave / Facing Couples" rule. Therefore, the starting formation is the 2x4 T-Bone formation where the Ends are in Facing Lines and the Centers are in a Starting DPT. >From this position, Grand Chain Eight is not legal. However, you could call 'Ends work Split: all Grand Chain Eight'.

From Diamonds, Ends are also to be Ends of Lines. Therefore, from the starting position mentioned above, I'd expect the Ends to do their part of Grand Chain Eight (i.e., right pull by, move along to the next End, and courtesy turn), working with the Ends, and never touching the Centers). We call 'Eight By' from here a lot. What do the Centers do? I don't know.

Suppose we had a Squared Set, then have Everyone 1/4 In. Can we call a Grand Chain Eight from here? I've never called it, although I've thought perhaps we could do a right pull by, and courtesy turn the next, to end in a squared set rotated by 45 degrees. However, I am dubious of the the legality of this.

I recently came across an old call, All Eight Chain, which is exactly as I just described.

See http://www.ceder.net/oldcalls/viewsingle.php?RecordId=53