The original tiny blocks were damaged by the boom as the boom would collide into they if over rotated.
So I added a pair of cheek blocks on the mast to use that works fine.
Those parts on the boom were used as a cunningham to control the slot between the jib and the main sail. This was achieved with the use of a stainless steel ring that pull the jib sheet towards the mast. One ring per side. I abandon this system to simplify my rigging. I did try different variations but abandon those too again to simplify my rigging.
I hope this is helpful.