https://www.bricklink.com/v2/catalog/catalogitem.page?P=18939c01&name=Technic, Turntable Large Type 3 Base with Black Technic Turntable Large Type 3 Top, 60 Tooth (18939 / 18938)&category=[Technic]#T=C
Is this the lego turntable your referring to or the one your superstructure is built with? I have built the crane with your superstructure using the directions in gmk topic. I wonder how change I’d have to make using the 60t turntable.
can you please provide me a link to your turntable supports?