DIY re-rigging your UFO

I am currently re-rigging Tarraleah a UFO of 29 years. She was launched in Fremantle Western Australia with her mast in a tabernacle. We are her second owners and have sailed to Lord Howe I. twice, a voyage of about 3-4 days, as well as to the Whitsunday Is. This is her second re-rig, the first occuring after we dismasted 50 nM off the east coast of New South Wales as the result of the starboard cap shroud U-bolt failing. We salvaged the mast (somewhat bent) by winching it aboard and motored back to a marina. It is now 16 years since the new mast and rigging and I plan to keep the re-rigging cost down by sourcing the terminals and wire and doing the re-rigging myself.What I would like some knowlegeable UFO owner to tell me is why the internal supporting rigging that is part of the frame that supports the U bolts is of such a small size in comparison to the external rigging. On Tarraleah the lower shrouds are 8 mm, the caps are 7 mm and these inner "cables" are 5.5 mm! The diagrams from Holman and Pye specify 1/4". I would have thought that the load on the U bolts would be transmitted to these cables or is that the frame takes the load? If so, why have the inner rig?My second problem is withdrawing the forestay up the foil of the furler. The SS pin that holds the rigging toggle is frozen in the mast bracket. I have belted it with a hammer but no movement so far. I was about to take a butane torch to it today but the weather turned nasty and I will wait for better conditions. I can't see anyway of getting it out unless I make a press or something to push the pin out. Not the easiest place to work, standing on a rope ladder 10 m plus up in the sky.
Barry G