Doug, most of those machines are set up so you must play maximum credits to to get the highest payouts. Not much different than the single denomination machines. I suggest playing machines that have 100%+ payback with optimum play. Palms and Fiesta I think are the best two locations. I hate playing slot machines but my wife enjoys them so I send her to the Palms to play the progressive Dueces Wild slots. As slow as she plays they are worth probably $5-$7 per hour. She has fun. Expect $2500 swings on these.