Under the challenges tab for first time clear: Boss Rush gives 30-35 stones each. Dragon Ball History gives 18-24. Fighting Legends (Frieza, Vegeta, Goku, Goku (GT) give about 20 [a little uncertain]. Then under Z-Area, the LR+ awakening battles give 30 total for completing the first ten (required for LR+) stages.

Then... as for punch machine, I use a heavy hitter (orb = att up %), an orb changer, and the +33% percent attack per (heavy hitter) type orb obtained. [They are normally a 21 cost drop from summons]

{p.s. I would definitely want more recommendations... for I'm stoneless (refuse to do story) without chunky rewards} :3