hello
i understand all what you said, i will try to explain you how i did it with my bad english.
1º i cutted a peice of metal in 14 equal pieces
2º then i shaped them with a heavy tool , i don´t know how it is call in english , it´s a machine that hve an abrasive disc!
3 º i shaped them to almost finl step with a "rasp " i think its caaled like that
4º drilled a hole and with the rasp i made the corners
hope you understand
now about the possibility of adjusting heigt you can make a hole and them make in the hole the shape of a screw but you will have to redesign the shape of all things