ozzie-crawl

never heard that about props, 30mm is 30 mm, a y537/3 is a 37mm prop 1.5" pitch and 3 blades
s215 is 40mm prop 1.6 " pitch
your carbon props should be 1.4 or 1.6 inch pitch,more likely 1.4" a 38-40mm would be a good start