Here is a pic of my mainsheet system using Ronstan block’s.
I’m a past employee of Ronstan and these days, both a supplier too and customer of Ronstan for components for stainless wire balustrading.
So this boat other than some Allen micro flip flop blocks in the tunnel and the below deck furler, is a complete Ronstan fit out.
These mainsheet/ Orbit blocks have a unique attachment method that with spectra loops (which extra long loops can be either made or be separately purchased) allow ideally the mainsheet to run through them without any friction or need to hang the block through a saddle or thimble.
David Williamson
The Flying Fifteen Blog 