Sorry I can't, but in case it is any use, we used twins for thousands of miles during our circumnavigation and used large rings on each side of the mast with no problems
See our yacht (only one pole up in this pic, page down to see last picture, the twins are set but due to wind direction only one pole set).
Have you visited the Blue Water Cruising Site <A target="_blank" HREF=http://www.onpassage.com>http://www.onpassage.com ?
Ratsey & Lapthorn, Cowes, are your people here. They developed the system commercially and we reviewed it in detail in YM back in the mid '90s. It's a good system if you don't want to carry specialist down wind sails, but it is quite expensive and takes a bit of time to set up so is best for passages with guaranteed long running legs (eg transAtlantic)
I have just purchased a Twistle Rig and tried it out a couple of weekends ago. The guy to talk to is Den Maidment - Tel: 02380 472422 or mobile 07860 346373 his email address is den@maidsure.freeserve.com. Although we only sailed with the rig for about an hour in Southampton water, it was simple to set up and set well without any regular adjustments. I have photos which I can send to you if you would like to contact me by e-mail (pnewns@ndsuk.com). The price of the rig depends on the size of yacht. Ours was about £800 including twin poles for a HR352. Obviously, you willl aslo need twi matching headsails - not too large!