the hair appears after the first ppf
Quick through a 150 S mesh requires very little pressure and even the slightest to much pressure starts to push the ink into the shirts. double stroking will push the first printed ink into the shirts and cause the shirt fibers to wick and stand up. It's a reaction of dry cotton fibers absorbing liquid.
Really try to get away from double stroke, a single hit of quick is all you need. If you "think" it's not white enough.. that's you because I've printed single bases for years and my whites and highlights are WHITE when they exit the dryer.