Well, at a minimum, you really need to get lots of ultra-thin CA glue liberally down into those cracks, even if you want to leave the cracks "open" at the top, although, honest answer, that piece, and the way you're cutting it, is very risky to build that way. There's a high chance you'll blow it apart grinding it down, and it really should have a backer when you work it. There's also a good chance, if it's dropped and lands the wrong way, you could blow out pieces.
I'd get it all put together and get more thin CA down in those cracks after you're done shaping it. It's going to be structurally weak, without any pins, dovetails or anything to lock it together but the glue.
As far as gluing it down and on the edges, yeah, speedbonder should be good, but be very careful with prep. I personally, would steer the customer away from this though (well, I'd flat out refuse, but I'm that way), at a very minimum, I'd glue the mammoth (before you shape the bolster side) the middle spacer, and the wood to a g10 backer/spacer, then, cut/grind the front edge, and maybe eliminate that front spacer. At least at this point you've got it all anchored down to a solid piece, other than the actual metal liners, which will move differently based on environmental factors, and are the weak adhesion point anyway. That way you've also got an entirely self contained "scale" to work with, instead of little strips with cracks running all through them.
Don't get me wrong, I love me some fucked up cracked to hell and back ivory, but I'm careful to make sure there's a solid foundation below those features, and I buy ultra thin CA glue in bulk.
