Yawl !
So we sorted out the RS Racing 5.8 and possibly helped a fellow Cremaster with a mast for his KA's.
Now my last possible match up ( all other sails, Norths, have matching masts ) question relates to this RS4 7.8 on a Fiberspar QT6000 490 .
Set it to stated out haul but added 2cm downhaul .
Scary stuff this , gave the cremaster muscle a good workout using the rig winch, could have swore something was going to go SNAP !!!
Cams had loads of pressure on them and both cams immediatley above and below the boom wouldnt rotate with out being given a decent hit to get them round .
Anyway attached pics for those in the know to again provide fantastic and helpful advice. Sorry should have rotated the pictures so hope no necks get tweeked

Oh yeah bigger sail so had to get older child to downhaul this one ( dad joke )
Thanks again for all and any help .
Darty