I just looked on the boat, with all your advice in mind, and decided I will leave things the way they are for now. Taking off the boom seems inevitable and I do not think the condition of the lines warrant this task.
I can't believe they would make it so difficult for such a simple thing...
I took some pictures of both ends, and the sliding eye that I'm still curious as to its purpose.
They are in my gallery, I still can't post a link.
Sailormann -"Make sure that you don't have your boom upside down as there are tracks on the top and on the bottom of the Isomat boom, and the movable eyes that you are describing usually run along the bottom track..."
The way the sheaves on the aft end are set up it appears to be right...??
Thank you, all have been extremely helpful .