There were simply too many ceramists in Brooklyn for Bklyn Clay’s original location, a 2,500-square-foot storefront in South Slope, which opened in 2016 before half the borough developed strong opinions on using, say, wet versus dry glaze. So owner Jennifer Waverek closed up shop and signed a ten-year lease for a Prospect Heights spot that’s more than double the size (it’s the largest of its kind in Brooklyn) with triple the amenities. The new location —