Turns out that seat posts (with the end cut off) fit nicely, well the actually they are a tight fit, over goose neck posts.... Have a look at the picture. I took a piece of 1/8 x 1 inch metal strap from a local hardware store and bent it in the vice to the "c" shape and drilled some holes to bolt it into the final assembly. I am sure you can find this part somewhere and you dont have to make it but I dont know where to buy them, I just know they exist.