Yes, sorry I never made it to Medway. A knee op stopped that. Basically I use a single piece of elastic which runs from the outer ends of each pole, down through the centre of each pole, into the main boom at two points half way down the main boom, then each strand of bungee runs around its own pulley at the stern-most (outermost point) of the Main Boom and around one pulley at the mast end of the Main Boom (if you follow all that – draw it all out on a piece of paper).
There are two small pulley blocks hanging off the normal spinnaker pole ring on the mast and I pull the poles out to these small blocks using a fixed length cord running through two cleats on the mast, fixed just above the boom (I am sure you know what I mean here). Running through the centre of each pole is also a fixed length of dyneema (non-stretchy) which is fixed at one end just behind the place where the bungees enter the main boom and the other end has rings (at the outermost pole end) through which each spinnaker sheets passes. When the pole that is needed is pulled out in position the dyneema becomes taught and the ring is located firmly at the pole end thus locating the spinnaker sheet (which is now the guy) at that point as well. You’re brilliant if you manage to follow all this!
I will try and take some photos and display.