Just looking at previous set lists from similar legacy artists at the iHeart festival. You can expect anywhere from 5 to 8 songs from Fleetwood Mac. U2 had the longest set of 8 songs in the last three years at iHeart in Vegas. Fleetwood Mac is probably the oldest group that has ever played iHeart. Older solo artists like Elton and McCartney have played iHeart though. Elton played 5 songs and McCartney played 8. iHeart usually caters to a younger more mainstream radio crowd.