Just got back from a few days of fishing that river. I alternate between fly and spinning tackle depending on the conditions. Both tackle types produced fish to 18". I probably caught 70 trout in 4 days with most being 12 inches or greater. I likely had 5 or 6 fish 15" or greater. The little J has a much better average size than i see on most creeks in PA.
Btw, 18" rainbow was on a size 20 dry fly at 9:30pm.