Hi Peter,
The lack of cleats for the uphaul may be because some systems had no adjustment of pole height or used a series of knots in a plastic fitting with "V" grooves in each end to adjust the height.
The uphaul needs to be strong enough to resist the force of the guy in the reaching hook, so you need NO ELASTIC in it. I would add a cleat at the base of the mast or run it around a block on the stowage bulkhead and then back to a cleat on the aft edge of the daggerboard case so it is easy for the helm to adjust.
The downhaul needs to be rope from where the pole attaches to the pulley at the base of the mast. You need a stopper knot here, so the pole can't go too high. After this you need elastic to take up the slack when the uphaul/downhaul is not in use. Run the elastic to the block near the bow and then back to mast (no end of other ways of running this). I would use 5mm diameter elastic, so long as that goes around your blocks OK. With a fly-away system, you need more "travel" on the downhaul than with end to end, so these can be more complex.
The uphaul and downhaul are connected where the pole attaches. At least 3 ways of attaching the pole, hook and eye, loop and ramp, and the knot and "V" groove I've already mentioned. With the loop and ramp the pole remains inside the loop, so has to be stowed along the boom.
There are some photos of Ben and Matt's system using a end to end pole with loop and ramp here
picasaweb.google.co.uk/lulhamrobinson/Sp...1sRgCMTDk-PY-M3xkgE# and some more of them using a spinnaker here
picasaweb.google.co.uk/lulhamrobinson/Wh...#5332750164115867698 but this time with an "end to end" system.
I hope this helps, let me know if you need more help.