I'm not sure about USA pipe sizes. But there is a good selection of sizes here in the UK.
Plumbing pipes here are 8, 10, 15, 22, 28, 36, 52mm. No end of fittings options. I've settled on 22mm pipe with 22mm to 15mm reducers to use 15mm hosetails with an 8mm diameter spout. 8mm diameter fibreglass wick slides through the horsetail like a penguin through a trap door.... Awsome fit.