I have 2 winecup ninebark bushes that I am unable to find pruning advice nor mature size info.
I can't find any reference to "winecup ninebark" so something in your name is amiss, I fear. Post a picture on any of the web plant ID sites and get a firm ID. We'll go from there. If it is ninebark, Physocarpus, treat it like many flowering shrubs. It blooms in the spring; prune right after bloom is over - definitely before July 4. Pruning after that will be removing next year's blooms. Remove 1/3 of the oldest stems every year to contain the overall size and keep young, more heavily blooming stems. Ninebark is prone to powdery mildew in hot, dry weather so I like to make sure there is good air circulation, especially at the bottom where the arching stems reach the ground.