Maybe an itemized list of what each chore entails would help him focus on what to do next?
ie. dishes means 1. clear table 2. rinse dishes 3. load dishwasher 4. wash large items 5. wipe counters and table
or something like that?
Otherwise, maybe a time limit? If chore x is done within x minutes, your pocket money is all yours. For every extra ten minutes, you lose x amount of pocket money?
Time is money - that's a real life issue. Learning efficiency is important for life.

Good luck with that! And keep your sense of humour!