Splicing.

http://www.rs-association.com/docs/tuning/splicing.jpg Hope this helps

The RS link is useful and explains how to splice dynema type core end to end.  This is what I referred to for my kicker arrangement.  Alternatively, the Kingfisher Evolution Breeze, seems like an interesting option which would not leave the internal core exposed after splicing.  I believe LDC have this and the splicing needle.

I used the excel control and yes its hard to splice until you work out how best to milk the needle through the line, BUT once its done it looks so much better than ropes where the inner is spliced.

I ended up using the Rooster fid with the Excel Control. My first attempts in the Dinghy park were hopeless because I had not tapered the outer core enough and it is easy to end up with a lumpy splice. My number one tip is practice the splice at home again and again. If the core does not pull through reasonably easy, do it again. Then when it comes to the dinghy part it should be straight forward. Double check the rope run before starting the splice (I speak from experience!) . Tools I used were exactly as per the Rooster vid + a piece of board to work on to save the boats decks, and very sharp nail scissors for trimming the outer core.