The teak beam is primarily for ease of fixing - but also brings the traveller back a little.
The bridge deck is double skin, cored, about 65mm apart. The three fixings either side of the cockpit well will have to be through bolted, with the core filled. The beam is fixed through bolted to three stainless brackets, below, enabling the fixings to go below the cored section.
I'm not into actually buying teak ! - I was working on a school a while before Chrismas - refurbishment of the science labs - and they were throwing everything out. The worktop edges were all solid teak - so I've got about 10 lengths about 10 foot long. It's also very good quality stuff - about 70mm x 32mm.

First part of the new rigging is all made up - so short of pulling two wires up the mast conduit, the mast can go up and stay up. The new lowers, babystay and backstay bridles will be measured with the mast up - then changed over with the mast up.

Just have to decide on the GPS - I'm more or less settled on simple fixed gps, with maybe a Yeoman plotter. However, a local supplier has an amazing price on the Raymarine 425 plotter - this has quite reasonable data pages if you don't want to bother with its plotter features. I'm sort of settled on the 152 Garmin though - mainly due to the single data feature, which fills the whole display with one selectable data readout. It also appears to have a clearer display than the 126/8 - but I'll take a look at two side by side. MES is nearby in Bristol - so at least I can go down there and see them up and running.

Decided on fitting a traveller for the main sheet - as with the later invaders - after a bit of measurement of boom etc. The normal position is on the extreme edge of the bridge deck - but this is an awkward place to fix to. Also, it better a little further aft, as my boom is longer than the later invaders.
I'm altering the end of boom fixing - leaving that for the topping lift - introducing two new Holt ring fittings at about 2' from the end. The top sheeting will be two single blocks with the sheeting split between them, spreading the load.

This beam is made of two pieces of my freeby teak, bolted together with similar packers. The white infill are just bits of leftover Treadmaster set into a routered out shallow recess - hides most of the fixing holes - breaks up the lines of the thing and generally looks sort of tidy - as its going to sitting in the cockpit in a fairly prominent position. The track then bolts right through this beam at the aft edge - then either side down through forward of the cockpit lockers with 100mm M5's -

While I was at Bristol Rope and twine getting the rigging made up I picked up some genoa sheet stuff. They do a 10mm matt polyester, Italian make I think, for 60 pence a metre ! so I invested all of about 15 quid in 20m - so will see what it's like.