Hi Albooboo
First off, that is a nice little kink in the trunk, would've been my choice as well.
There is however a huge problem of size.....or rather the lack of it
A better artist than me might be able to find a tree in there, but from what I've experienced the angular growth pattern would make that difficult
I've found that smaller cuts close over relatively quickly, so most likely the best course of action would be to plant it in the ground or a larger container to allow it to fatten up.......build a trunk you can use and then chop back and start the design.
I don't know about grafting, but the way they back-bud it really shouldn't be necessary.
I air-layered the top off mine, I don't have the layer anymore but it's still alive even after a hectic ant/scale attack that the owner didn't notice, so they are tough....
Regarding what you can get away with now, I've had this plant for a while but never had a plan with it. We had a pathetic excuse of a winter, even for the desert, and a few weeks ago I got itchy fingers and start poking around in the topsoil to see what the root situation is, had a slight mishap

and ended up bare-rooting, root pruning and potting the tree.
.....Doesn't look like it even missed a beat.
They are extremely tough, but please keep the difference in climate in mind.
I have to say, I was about to give up on ever getting mine into shape, but after reading up on this species I'm determined to bonsai it, even if it's not the best tree.
Cheers
Gerhard