I have had success repairing cracks on curved surfaces by putting a piece of surgical gauze tape over the crack on the inside and soaking it in CA. This critter has no bracking inside and would be almost impossible to fit cleats but the gauze tape worked perfectly
Once you get the crack closed and stable you can figure out what kind of cosmetic repairs you want to do - I often only drop fill the crack and scrape it back. Sometimes I'll rub parafine along the edges of the crack to keep CA from flowing out onto the finish.
I've also learned a little trick when applying cleats - if it is a flat surface inside the guitar I put the cleat on one jaw of a clamp by wrapping masking tape back on itself to make sort of weak double sticky tape. I'll also put a piece of tape on the screw part of the jaw to keep it from turning (not shown in this picture)
When I reach inside the guitar I line the outer jaw with the line of the crack (with some sort of caul) - then I know the cleat is centered over the crack on the inside. Snug up the clamp, when you get ready to remove it the masking tape releases easily
(The top on this guitar had been bumped - was both cracked and separated at the side joint. Used Titebond to get some working time)