Mike – as we did not get the demo at Medway (hope you are back racing soon) could you give some more details about your system.
Do you use a single piece of elastic or one for each side?
What purchase is on the elastic inside the boom?
I assume that the overall length of the pole is from the mast end fitting on the pole to the outside of the ring where the sheet runs.
I have had a quick look at the P&B catalogue in the National pack and I think a twin pole manual system can be done for less than the price of a new pole until you add in the boom blocks and replacement strings. I intend to have a play with this set up as soon as I can get my head around all the details.