Anglers need to carry a thorough assortment of nymphs and dry flies to match the PMD hatch. As far as nymphs/emergers are concerned, I would recommend carrying #18 Barr's Emerger (PMD), #18 Mitchell's Split Case (I like the Baetis version best to match this hatch), #18 Flashback Pheasant Tail, and #18 Mercer's Trigger Nymph (PMD). These patterns should be fished mid-column.
During the peak of the hatch when the trout are keying on duns, I would recommend carrying #18 Mathew's Sparkle, #18 Cannon's Snowshoe Dun, #18 Barr's Vis-a-Dun, and #18 Stalcup's CDC Biot Comparadun. The best dry fly fishing has been on overcast days.