Been doing demo on and off for about 15 years, and the chunk size debate comes up every single time. My take: big chunks win, but only if you score the slab first. Cutting the slab into a grid with a saw before you touch it with the breaker changes everything. Instead of chasing random fractures across the yard, each square pops loose clean and you know exactly where the next one is. Grid it up, then break along your cut lines and the pieces come off in slabs big enugh to grab with two hands or a skid steer bucket if you can rent one. Watch your depth on the saw though, you only need to score it, not cut all the way through.
Load out is where people lose money. Get the dumpster or trailer right next to the work, not out by the curb. Every extra step with a 40 pound chunk adds up fast. And keep a pry bar handy, tipping a chunk up onto a dolly beats deadlifting it off the dirt every time.
Last thing, check for plumbing or conduit before you saw. I nicked a water line once because I skipped the locate call. Cost me a weekend.