I have a N5.7 and have had the same problem finding info.I think that what you are refering to are the jib blocks. On the Hobie 16 they are attached to tracks on the main beam. on the N5.7 thet are either attached to similar tracks that run along the sides of the tramp behind the rear stays, (at least that's where mine are), or, attached to the tramp just inside the rear stays.if there are no tracks along the tramp, you may need to find another cat that has them set up on the tramp and copy it. the positioning of these will depend on the cut of your Jib.
You are going to love the 5.7. The ride is smooth as silk compared to the round bottom cats wit boards. Very fast.
I have done a lot of work to mine so if you have any questions keep posting and i'll try to help